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Fish Farming

Handling and care of fish

Fish are fun to catch and nutritious to eat. They are high in protein, rich in vitamins and minerals, and low in saturated fat. Fish oils are high in polyunsaturated fats that may function in lowering blood cholesterol. Proper handling of fish from the time you catch them until you get them to the table will help maintain optimum eating quality. Keep the following fish handling tips in mind.

Care on the Water

  • Keep fish alive as long as possible. Fish flesh is very perishable.
  • A metal link basket or live box is best. A stringer can damage the flesh and increase chances of bacterial contamination.
  • If the water is warm, place the fish on ice or keep them in cool water.
  • Don’t toss fish into the bottom of the boat where they will dry out or where their flesh may become bruised and susceptible to contamination.
  • Keep fish out of sunlight and direct heat.

During winter fishing trips, keep fish covered to prevent them from freezing and drying out.

  • For optimal eating quality, fish should not be frozen by throwing them out onto the ice.
  • Put fish in an ice chest or styrofoam cooler to prevent freezing and dehydration. Clean them prior to freezing.

Check fish for signs of disease or parasites

  • A healthy fish should have firm flesh with no signs of discoloration/browning, a mild fresh smell, bright clear eyes and red gills.
  • A diseased fish may have sunken eyes or “pop-eyes,” discolored skin, loose scales, open wounds or gills that are white and slimy or bloody.
  • In some cases, the fish is edible if the diseased area is removed. Fish should be thoroughly cooked.
  • After removing the usable flesh, do not throw the remains back in the water. Dispose of them properly Decide on the fate of the fish immediately. If you do not want them, release them right away instead of waiting to decide at the end of the day, when they may have a reduced chance for survival.
  • Check with your local game and fish representative if you find abnormal growths in the flesh.

Fish in safe waters

  • Some waters may be contaminated by pesticides or other substances. For information on the safety of fishing waters, contact your local health department.
  • Contaminants are concentrated in the fatty parts of the fish. To reduce your risk of consuming contaminants, remove the skin and fat deposits when you clean fish, or use fillets instead of whole fish. Choose a cooking method that removes additional fat, such as baking, broiling or charbroiling.

Care in Cleaning and Storage

  • Clean and cool fish as soon as possible. Time and heat can rob freshness and flavour.
  • Fish spoil rapidly due to their strong digestive juices. If fish are not cleaned promptly, off flavours may develop.
  • You will need a sharp knife, a clean towel or paper towels (to wipe the fish after rinsing), plastic bags and crushed ice in an ice chest.
  • Use a clean fillet knife to clean the fish. Bleed the fish. Cut the throat as you would any game animal, and remove the gills and entrails. Wipe the surface of the fish with a clean cloth or paper towel, put the fish in a plastic bag, and put on ice.
  • If making fillets, rinse the fish in clean cold water to remove blood, bacteria and enzymes.

Don’t cross-contaminate. Clean the knife after each use.

  • When you clean fish at home, wash your hands, the knife and the cutting board with warm soapy water after each use.

Store cleaned, fresh fish in the refrigerator at 40 F or lower in a covered container and

use within two days.

  • Fish should be kept moist but not wet.


 Cleaned fish may be frozen whole or as fillets.

  • Traditionally, fish have been frozen whole, as they come from the water. This practice is not recommended, because deterioration may occur, and poor eating quality may result.
  • Improperly wrapped frozen fish may become dehydrated — that is, suffer “freezer burn”—due to contact with air. This condition negatively affects taste and texture.
  • Divide fish into family-size servings and use a plastic cling-type wrap as an inner covering and moisture/vapor-proof freezer wrap as an outer covering. Bread bags, waxed paper and cellophane wraps are poor freezer wraps.
  • Remember to press air from the package to help prevent off-flavors or odors characteristic of rancidity.
  • If freezer space is available,smaller fish may be placed in water in plastic containers, in clean wax- or plastic-lined milk containers, and then frozen.
  • Label each package with the contents and date.
  • The temperature of the freezer should be 0 F or lower. When freezing large amounts of food, scatter the packages throughout the freezer so the food freezes quickly.

Care in Preparation and Preservation

Prepare fish properly. Cook fish until it flakes with a fork.

  • Don’t cross-contaminate. Keep raw fish and cooked fish separate.
  • Thaw fillets in the refrigerator, in the microwave or under cold running water. Food defrosted in the microwave should be cooked immediately. Other thawed fish should be used within one to two days.
  • Undercooking fish can be risky, while overcooking can result in an unpalatable product.
  • Fish is generally low in fat and very tender. Moist heat cooking methods are unnecessary. Methods that develop flavour, such as broiling, baking or frying, are preferred.

Fish may be safely preserved by proper smoking procedures.

  • After cleaning the fish, cut it into uniform pieces. Do not allow fish to stand unrefrigerated for more than two hours.
  • Salt is a preservative. Fish must be salted in the proper brine solution for an appropriate length of time. Generally, soaking the fish in a strong brine (1 cup salt/7 cups water) for 1 hour is adequate.
  • After salting, the fish must be heated to an internal temperature of 160 F and held at this temperature for at least 30 minutes during the smoking cycle.
  • Store smoked fish in the refrigerator if it is to be used within two weeks.
  • For long-term storage, smoked fish should be frozen. It also may be preserved by following current pressure canning recommendations.




Fish keepers start out with a few tropical fish or maybe some gold fish in a small aquarium. But they soon want to know more about how their fish live, and especially how they breed.

General aspects of fish breeding, just like with fish keeping, include proper feeding and providing the right environment. The breeding environment needs to be maintained with proper water conditions and you need to watch for disease or other ailments.

Some fish are easy to breed and will readily spawn in a community tank. But most fish need a bit more help. Understanding the spawning behaviours and needs for the particular type of fish will make fish breeding successful and rewarding.

Carefully selecting the “brood stock” (parent fish) and condition them on a good varied diet is important. A fish breeding tank is needed for many species as well. The breeding aquarium needs to have the right water conditions to stimulate spawning and for the eggs to hatch. Consideration also needs to be given to the fry and their survival. The first foods for the fry, before they become free swimming, and foods for the fry to grow are important. It’s also important that they are protected and have places to hide.

For first timers, or those who are new to the hobby, it’s advisable to start out with some of the easy to breed livebearers. These include the Guppies and Platies. Then move on to some of the hardy egg-layers, like Danios and Barbs. Experience with these initial undertakings will greatly help in keeping and breeding many other types of fish, including some of the very difficult species.


Breeding Anabantoids (Labyrinth Fish)

Most anabantoids, like gouramis and betta fish, are bubble-nest builders. The nest is built and maintained by the male. Male anabantiods will take some time to build a nest of bubbles in floating debris or plants. They entice their mates under the nest and induce them to lay their eggs by giving them a spawning embrace. The eggs are immediately fertilized and placed in the nest by the male who guards them and later, the fry against all intruders.

In the aquarium, an upturned butter dish or something similar can serve as the anchor for the nest. This is usually not necessary though if there are plenty of plants, especially floating plants like hornwort, in the aquarium. The breeding tank is usually small (5 or 10 gallons) and shallow with lots of hiding places for the female (plants and rocks). After the male and female are placed in the tank, the bubble nest is usually built within a few days.

The female can be removed after spawning because the male may become aggressive towards her. The male will then watch over the eggs until they hatch 24 to 30 hours later. The temperature should be about 80° F with a lower temperature extending the hatching time and a higher temperature decreasing it. After hatching, the fry will absorb the yolk sac in two or three days. The fry will not be large enough to eat baby brine shrimp for several days so they must be fed infusoria or cooked egg yolk squeezed through a cloth.

The larger anabantoids are easier to breed mainly because the fry is large enough to eat baby brine or pulverized flake food. For example, dwarf gouramis are harder because the fry is so small they need infusoria to survive the first week or so of life.

Breeding Cichlids

Cichlids fall into several different groupings with different breeding habits. Almost all Cichlids are either “substratum-spawning” or “mouth brooders”. This means they either lay the eggs on some portion of the substratum, (including pits dug in the sand, leaves, and flat rocks), or they take the eggs and fry into their mouths to protect them from predators. Another, and more important distinction, if you are planning to breed Cichlids, is whether they are monogamous or polygamous.

Monogamous cichlids vs Polygamous cichlids:

Monogamous cichlids 
Monogamous cichlids pair off when allowed to interact freely in the aquarium. Therefore, about six or more young fish should be purchased and grown up in the same tank. As soon as they start pairing off, separate the pairs as they will claim a territory and defend it fiercely.

Pairs often have trouble because aggression results in a battered female. For this reason, many breeders set up barriers in the tank that only the female can pass through thus giving her a safe place away from the male. At the very least a lot of hiding places and maybe a few target fish can be introduced to the pair’s aquarium. The idea is that aggression is taken out on the target fish rather than the female of the pair. Suitable target fish should be fast like giant danios or botias or be able to dive into the gravel like some eels and loaches.
Polygamous cichlids 
Polygamous cichlids come in two varieties, open polygamy, where males and females consort freely among each other, and harem polygamy, where males maintain a territory with several females for an extended period of time. Harem polygamy is based on one male protecting several spawning sites from other males. The actual spawning sites are then claimed by each female within the male’s larger territory.

Females vigorously defend these actual spawning sites. Usually after spawning the male is no longer allowed near the spawning site and the female takes care of the eggs. This type of cichlid is usually marked by extreme sexual dimorphism, with the male being much larger and having more elaborate finnage.

To breed polygamous cichlids, you need a large enough area so that the male has a place to go after spawning so the female won’t batter or kill him. Fortunately, most harem polygamy cichlids are dwarfs so a 20-gallon aquarium may be large enough. Overturned clay pots can serve as spawning sites and plenty of plants are always welcome even though respawning activities may uproot them.

The biggest problem with open polygamy cichlids is that they are thought to form pairs, and being housed this way, the female almost always ends up battered or killed. To avoid this, you can either house them in a community situation with other cichlids (and thus run the risk of producing hybrids) or house a male with at least three or more females. This spreads the abuse out over all the fish which increases their chances of survival.

Almost all the open polygamy cichlids are mouth brooders which means the eggs and fry are carried by the female in her buccal cavity (mouth) until they are free swimming. The substratum spawning cichlids usually excavate pits in the substrate in which to lay their eggs. In both cases the parents will defend the eggs and fry until they are free swimming.

Referenced from Dr. Paul V. Loiselles’ excellent book, The Cichlid Aquarium, Tetra-Press, 1985.


Breeding Goldfish

Goldfish are generally easy to breed! They are a very social animal and do well when kept in groups. Goldfish typically shoal, forage and feed in groups and are likely to breed in groups as well. It is best to add oxygenating plants such as Anacharis in the aquarium for the spawning process and for eggs to adhere to.

To induce spawning, the temperature can be slowly dropped to around 11° C (60° F) and then slowly warmed until they spawn. This is done to mimic the conditions found in nature when spring arrives which is the only time they will spawn in the wild. Feeding lots of high protein food such live brine shrimp and worms during this time will also induce spawning.

Before spawning as the temperature increases, the male will chase the female in a non-aggressive way around the aquarium. This can last for several days. The colours of both fish will intensify, the male somewhat more than the female. During spawning the male will push the female against the plants while both fish gyrate from side to side. This stimulates the female to drop tiny eggs which the male will then fertilize. The eggs will stick to the plants by sticky threads. Spawning can last 2 or three hours and can produce up to 10,000 eggs. The parents, when finished will then eat as many eggs as they can find.

For this reason, it is best to remove the parents after spawning is complete. You will need to feed one of the various specialty foods for fry (see Foods for Fry) until they become big enough to eat flake or brine shrimp. At first the fry are a dark brown or black colour in order to better hide and not be eaten by larger fish. They gain their adult colour after several months and can be put in with larger fish once they reach about 1-inch long.

Breeding Killifish

Most species of Killifish are sexually dimorphic. Males are much more colourful than females and will have larger dorsal and anal fins. Having adapted to life in very diverse habitats, the Killifishes are divided into two groups based on different methods of reproduction that they employ. The first group of Killifish are those that are bottom spawners, pushing or burying their eggs in the substrate. The second group are the ‘egg-hangers’, those that usually spawn on plants to which the eggs then adhere.

Killifish are either of the short-lived seasonal or “annual” species or they are of the longer-lived non-annual species.


Seasonal or “Annual” Killifish species
Most surprisingly, some species that spawn on the bottom live a very short ‘seasonal’ life in mud puddles or flood plains. When the mud puddles dry up so do the fish, except for the eggs they left behind buried in the mud. When the rains come again, the next generation of fish is born to repeat this short life cycle.

Because the entire life span of these fish is no more than 8 months they are considered seasonal or annual fish. In the aquarium they also have a short life span, usually only up to about 1 1/2 years.
Non seasonal Killifish species
These are species that live where there is always water. Most will spawn on plants though there are a few species that spawn on the bottom. They produce eggs that will adhere to the plants. These fish are longer living in the wild, usually 3 to 4 years.

Many non-seasonal types of Killifish have a lifespan of 5 or more years in the aquarium


Breeding Livebearer Fish

Livebearers are generally very easy to breed. Like most other fish, the hard part is raising the fry. Generally, the parents and other fish in the tank become predators to newly hatched fry but there are several solutions to this problem.

The easiest solution to predation is to provide good cover and hiding places for the fry in the form of plant cover like anacharis* and hornwort*. This will help but some will still get eaten. Another solution is to buy a breeding net, which provides a separate compartment in the aquarium for the mother before she drops the fry. After dropping the fry, the mother can be removed so the fry is separated from the rest of the tank by the breeding net. Along the same lines the mother and fry can be placed in a separate aquarium so the mother can be separated from the fry when they are born. Breeding traps are also utilized which keep the mother confined with a grating that the fry can pass through.

The fry can be fed baby brine shrimp, which is usually purchased frozen, or can be hatched from brine shrimp eggs. Also pulverized flake food, which is sold as baby fish food, and hardboiled egg yolk strained through a cloth.


Breeding Catfish

There are many catfish species, but not all are successfully bred in the aquarium. There has been good success with the Coryadoras, but species like the Plecostomus simply require a large pond with mud banks for them to dig spawning areas. Their requirements just can’t be accommodated in home aquariums.


Breeding Corys (Armored Catfish)
Suggested water conditions for breeding: pH: 6.0-6.5, hardness: 4? dGH. To prepare a pair for breeding set up a tank with large leafed plants. Feed the pair plenty of mosquito larvae and other live foods. Spawning is stimulated with frequent water changes.

The Corys have a very interesting breeding routine. After bumping the male on the vent, the female will receive the males’ sperm into her mouth. She then discharges a few eggs which she catches and clasps with her ventral fins. Then the female will swim around and deposit a bit of sperm and just a few eggs at a time in select spots, such as on the underside of a selected leaf, some will deposit them on the heater tube or ever the aquarium glass.

When the female runs out of sperm, she will go back to the male and repeat the process until the spawn is complete. This will continue until about 100 eggs are deposited. Different species will put different amount of eggs on each leaf or other selected spots. After spawning the pair should be separated from the eggs. The eggs should be well aerated and treated to prevent fungus form growing on the eggs.

The fry will hatch after four or five days and can be fed rotifers, Artemia, nauplii, and the contents of fresh peas.


Breeding Characins (Egglayers)

Characins all breed the same, with just a few exceptions. Characins such as Tetras, Silver Dollars, Hatchetfish, Headstanders, and Leporinus are free spawning. This means they will discharge the eggs and sperm into the open water, though always around bushy planted areas.

It is best to spawn most characins by separating the males and females and then feeding them heavily on live foods until the females grow fat and the males become more colorful. Then introduce a female and a male into a specially prepared spawning tank.

The spawning tank can be a low aquarium (5 gallons to 20 gallons depending on the species) filled 3/4 full with clean, aged water and lined with a dense foliage about two inches thick. The Glowlight Tetra is an exception here, in that they don’t like the vegetation dense. You do not need any sand on the bottom but you can add a few pieces of wood or twigs with free space underneath to give the fry a place to attach. For the Neon Tetras, it is recommended that everything you place in the aquarium be sterilized, as well as the top. Other characins do not seem to need quite as much care to spawn successfully.

Usually an increase in temperature to about 780F (see individual species), feeding plenty of live foods, and covering the aquarium with a towel (to darken it and maintain temperature) will trigger spawning. Spawning usually takes place in 48 hours to a few days. The eggs of most characins are quite sticky and will then adhere to the foliage as they are dropped. Remove the parents as soon as they have completed spawning or the parents might eat the eggs.

The spawning aquarium temperature can then be increased to and maintained at about 800F. The eggs hatch quickly, usually in about 36 hours. The fry need to be fed infusoria, especially rotifers, for 1 to 4 weeks, depending on the species. Then they can eat brine shrimp.

The Congo Tetra is another exception here in that they spawn in temperatures of 770F , and their eggs take 6 days to hatch.


Breeding Cyprinids (Egglayers)

Most Cyprinids are free spawning. This means they will discharge the eggs and sperm into the open water. Cyprinids include Barbs, Danios, Rasbora, Chinese Algae Eater, Bala Shark, Red-tailed Sharks and Black-tailed sharks, to name a few.

With Cyprinids, usually an increase in temperature and feeding plenty of live foods will trigger spawning. The eggs will then adhere to whatever they come in contact with: leaves, decorations, gravel, etc. The eggs hatch quickly, usually within 30 hours at which time the fry can eat finely powdered flake food followed by baby brine shrimp after a week or so.

The parents will eat the eggs and the fry so some means of protecting the eggs is needed. To accomplish this, you can use spawning grass, marbles in the bottom of the aquarium, or a grating that the eggs can fall through but the parents cannot. After spawning it is a good idea to remove the parents.

One of the notable exceptions to this method of breeding is the practice of the Bitterling, Rhodeus sericeus amarus, who protects the eggs within the Mussel and defends them after they have hatched


Breeding Rainbowfish (Egglayers)

Rainbowfish spawn year round in their native habitat, and are easy to breed in captivity. Not only are Rainbowfish easy to breed, but their fry are not difficult to rear. Australia has strong restrictions on the exportation of live animals, so many of the Rainbowfish species that have become available were the result of eggs being airmailed to Europe and the United States. where they were hatched and the fry reared.

Rainbowfish have been found to breed most readily in the aquarium, especially after a water change. They will often even spawn in a community tank, but other fish and young rainbowfish will snack on the eggs. A breeding tank should be three or more feet long with aged water that is the same temperature as the species tank or a few degrees warmer. Use a thin layer of gravel or shell grit as a bottom substrate. The tank also needs to have a filter or be aerated. Provide either fine plants or an artificial spawning substrate for the eggs to adhere to and the hatched fry to hide in.

Introduce either a pair at a time or three male Rainbowfish of a similar size with two females. The male of most species will display a bright courtship stripe. The males will court the females by swimming around their partner in circles while displaying. They will also do a headstand, indicating (pointing to) the spawning site. A receptive female will follow the male to the site where the two will swim closely side by side. The fishes’ bodies and fins will vibrate for a few seconds as the sperm and eggs are released. Then they will quickly dart away, creating a whirling of the eggs and sperm.

After a spawn there can be from two to over 200 eggs. They each have a long thin thread which attaches the egg to the spawning substrate. The larvae hatch in 4-14 days, depending on the species and the temperature. They should be feed very tiny foods often, at least twice a day. Beginning foods can be commercial prepared fry foods, finely ground flakes, infusoria, and nauplii. They grow quickly and will soon be able to take larger sized foods. They will be fully grown in just a few months, but it takes two to three years for them to reach maturity.

A problem to be aware of is crossbreeding. Rainbowfish in the wild will not breed with fish of another species, even when presented the opportunity to do so. But for some reason, rainbowfish of the Melanotaeniidae family in the aquarium will interbreed, often with undesirable results. Somehow the fry of mismatched parents lose most of their coloration. Since many of these species are rare, it is desirable to keep the bloodlines distinct, or risk losing the beautiful coloration that nature has taken thousands of years to develop.


Breeding Perches – Archerfish

The archer fish have been bred in Australia by a commercial fish farm, Ausyfish Pty Ltd, according to Bruce Sambell commenting on the Archerfish page. According to Bruce they were spawned with hormone. About 10,000 eggs hatched. They were a variety which is strictly freshwater! Thanks goes to Bruce Sambell for this fascinating information and an introduction to his fish farm Ausyfish Pty Ltd.


Spawning Information:

  • Brood fish were collected from upper reaches in pure freshwater on Cape York, Queensland.
  • Fish were injected the first week of February 2007 after a “running” male was detected.
  • No obvious external sex differences. ·The female had a slightly enlarged abdomen but virtually no different to the running male.
  • Injected the fish with hormone at standard rate. (1 pair)
  • Male weight 145gms, Female weight 261gms
  • Water was maintained at 25C
  • PH 7.8
  • Larvae were pigmented.
  • From above the larvae appeared as bright white specks. From the side they appeared dark in colour. Under magnification, they looked like miniature version of the adult fish.
  • Larvae were fed newly hatched artemia.
  • After 7 days of feeding artemia, they were gradually converted to dried feeds.
  • Larvae grew very quickly at high temperatures but slowed dramatically when temperatures dropped. At 3 months old, tank raised larvae were 30mm. At 6 months old they were still 30mm
  • At 6 months old pond raised larvae had reached 13cm.




Fish feed is a major expenditure for fish farmers. Good fish feed management can reduce overall culture cost, improve fish farm environment and ensure healthy growth of fish stock. Fish feed management includes choosing the right feed, using a correct feeding method, calculating the feeding cost and ensuring the cost effectiveness of fish farm.


Nutritional requirement of a fish

Protein, fat, carbohydrates, vitamins and minerals are the essential nutrients for fish. Protein provides energy and builds muscles. Protein Fat provides fish with energy. A right amount of fat can improve taste and texture but excessive fat may pose a health hazard to fish. deficiency means slower growth whereas excessive protein will put up the feeding cost. Fat provides fish with energy. A right amount of fat can improve taste and texture but excessive fat may pose a health hazard to fish.

Carbohydrates provide energy but most of them are not easily digested by ordinary carnivorous manne speCles (e.g. roupeι apper and mangrove snapper). Vitamins and minerals are the essential trace elements that can enhance natural resistance and feed conversion rate. It is noteworthy that nutritional requirements of fish vary with different species, sizes, growth stages and feeding habits. For example, carnivorous fish require a higher intake of protein and fat than the omnivorous and herbivorous species, while marine fish require more protein and fat than freshwater fish do. For this reason, fish feed should be specifically chosen to suit different species.



Types of Fish Feed

Providing fish a nutritionally balanced diet is essential to grow a healthy stock of fish. In terms of fish farming, the variety of fish feed must be carefully considered because feed represents 50% of the production cost.  There are many different types of freshwater fish feed readily available today. One can provide a variety of food for their fish depending on their individual feeding requirements. While some aquarium fish may be able to survive on a limited variety of food, this does not necessarily mean that they are living up to their full potential. A wide variety of quality food within the species’ feeding parameter is beneficial for the long term health of the fish.


Processed Feed

Today, due to advancement in aquaculture feed, farmers and hobby fishkeepers both are able enjoy a greater variety and a better quality of commercially processed fish feed than ever before. Processed feeds are formulated to meet basic nutritional requirements of fish. Quality fish feeds are supplemented with proper vitamins and minerals as well. This makes processed feed a convenient source of staple food for most farm raised and aquarium fish. Processed dry feed includes flake, tablet, pellet, and crumb form. All of these feed come in many different sizes to incorporate all types of fish. Some dry feeds are designed to float, while other are designed to sink in order to incorporate bottom feeders. In fact, some pellets are even designed to stick to the surface of the aquarium glass in order to feed fish at mid-level. Premium fish feeds and medicated fish feeds are also commercially available for feeding fish with specialized needs.


Live Fish Food

Live fish food is an exceptionally good source of fish food. Since live food is not readily available to fish in an enclosed man-made environment, it can be beneficial to actively incorporate live food as part of their diet. Feeding live food is necessary for fish with specialized needs such as many carnivorous fish, wild specimen, and fry. Not only does live food mimic the feeding habit of fish in their natural environment, live food can provide many benefits that commercial feeds have not been able to replicate to this day. Many species of fry that have been grown with a supplement of live food have proved to have exceptionally better survival rates and grow to become one of the most robust specimen. Live organisms that are suitable for fish include bloodworms, blackworms, tubifex, glassworm, daphnia, grindal worms, white worms, and redworms among many others. Incorporating live fish food at least twice a week is recommended for most fish.


Fresh Food

Fresh foods are foods that are not processed prior to feeding. This category of fish food includes fresh vegetables and fresh meat. Fish with specialized dietary needs can greatly benefit from fresh food. For example, when attempting to condition fish for breeding, a high protein diet of fresh food is beneficial. There are many different types of fresh food that can be fed to fish.

Vegetable matters are readily accepted by herbivorous fish. While vegetable matter is low in fat and protein, they consist of much needed carbohydrates, fiber, and vitamins. Prior to feeding, vegetable can be blanched in order to break down the tough membranes. Vegetables that are commonly fed to a variety of aquarium fish includes romaine lettuce, spinach, cabbage, kale, watercress, zucchini, green peas, broccoli, cauliflower, beet tops, and strawberries.

Various types of meat can be fed to carnivorous fish.  Depending on the type of meat being fed, it is advisable to cook the meat prior to feeding in order to prevent introducing infectious disease to your fish. Meat containing high amounts of fat should be avoided or fed very sparingly in order to prevent digestive problems.  Since meat generally contains less water and carbohydrates than other sources of food, it is a great source of protein for your fish. Meats that are commonly fed to a variety of aquarium fish includes beef liver, beef heart, pork spleen, chicken, shrimp, herring, anchovy, smelt, mackerel, tuna, clam, mussel, scallop, oyster, crabs, and squid.


Frozen and Freeze-dried Food

Many types of frozen and freeze-dried foods specifically marketed for aquarium fish are readily available today. As the majority of the nutritional value is preserved in the frozen and freeze-dried form, it can be a valuable and convenient source of food for fish. Brine shrimp, plankton, krill and many other invertebrates are available in frozen form. Some frozen food marketed for aquarium fish are conveniently packaged for individual feedings. Many smaller invertebrates mentioned above are available in freeze-dried form as well. While the nutritional value is not equivalent to a live form, freeze-dried food is another great supplemental fish food for aquarium fish.


Using animal wastes in fishponds

Animal wastes flow

How animal wastes work in a pond

How animal wastes work in a pond

Direct feeding value of pure wastes is known to be poor. Wastes act by:

stimulating phytoplankton production; and acting as substrate for bacterial production (detritus) and as feed for zooplankton.

These two processes are strongly interlinked, since phytoplankton is a major source of detritus for bacterial production. Also, phytoplankton, through photosynthesis, is the chief producer of dissolved oxygen in the pond used by all organisms including fish.


Factors to consider before using animal wastes

  1. Are wastes available on-farm? If so, are the wastes already used? Should they be diverted for use in fish culture?

Livestock wastes are often important as crop fertilizers and fuel. Consider the opportunity costs.

  1. Is it worth raising livestock, especially to generate wastes for aquaculture? Consider:

costs/difficulties of doing so (e.g. feed availability and cost, marketing difficulties, technical abilities and interest of farmers); and

inorganics are now cheaper to use than livestock manure in many places



 Management factors to consider

  1. Are all wastes to be used in fish culture?

If wastes are to be used elsewhere, they should be collectible prior to entering the pond (e.g. use a sump). Also, wastes should be available in larger quantities at certain periods when their use should be reduced for fish culture (e.g. during the cool season).


  1. Can all wastes be collected?

Feedlot livestock are kept confined at all times so all the wastes can be collected and used.

Small-scale farmers often allow livestock to graze or scavenge during the day and only confine these at night. This reduces feed costs considerably, often allowing only on-farm or low-cost, supplementary feeds to be given. However, collectible wastes will be less.


  1. Livestock may be penned at the farmer’s house for security or traditional reason; this may limit potential advantages of integration. Labour is required to collect or prepare livestock feed.


  1. Ponds may be multifunctional. Large animals are usually denied access to the pond because entry to and wallowing in it can destroy the dikes and cause turbidity which reduces natural food production.

Livestock wastes vary in terms of both quantity and quality which are affected by the following:

– food quality of livestock
– species (monogastrics and ruminants) and size
– stage in life cycle (breeder, grower, etc.)
– solids only or mixed with urine
– amount of waste feed
– contamination with bedding materials, rainwater, soil, etc.
– method and period of storage


Layout/design options


On the pond dike

On the pond dike

Pens close to the pond to reduce labour cost of loading waste

Over the pond

Over the pond

Pens are cooler and more humid

In the layout/design aspect, consider:
– size and number of livestock;
– space availability/land cost; and
– relative cost of materials


Design the pond to allow limited access.

Fence around pond keeps buffalo out

Fence around pond keeps buffalo out.

Fence across pond lets buffalo in water.

Fence across pond lets buffalo in water.

Pigs and chickens

Pigs and chickens are monogastrics. They are fed a high-quality diet and their waste is high in nutrients.

Buffalos and cows are ruminants.

Buffalos and cows are ruminants. They are given a diet low in nutrients and their waste is low in nutrients. However, they are cheap to feed.


Miscellaneous facts

Young livestock tend to feed on diets higher in protein so their waste has more nitrogen and is better as a pond input.

Ruminants’ faeces contain high levels of carbon relative to nitrogen and discolour the water. Generally used alone, they give low-fish yields. Consider use of ruminants’ urine as it contains a better balance of nutrients.

Laying hens are fed different diets than broiler chickens and their waste is particularly high in phosphorus.


Tips for proper waste application

First application can be done about 1-2 weeks before fish stocking to produce natural food for immediate fish consumption.

Apply or load manure after sunrise (about mid-morning).

Maintain a regular schedule or routine of application.

Make sure that freshwater is available for flushing in case of direct oxygen depletion.

Scrape off 2-5 cm of the pond bottom soil during pond preparation. This can serve as an excellent fertilizer for vegetables.


Water quality management

Too much manure when loaded in fishponds can cause dissolved oxygen depletion resulting in fish mortalities. When manure loading is excessively high, too much decomposition occurs; thus, the biological oxygen demand is high, using up the available dissolved oxygen.

Phytoplankton produces dissolved oxygen during the day but consumes it at night. Another source of dissolved oxygen in a static water is diffusion of atmospheric oxygen.


Indicators of low dissolved oxygen

  1. When plenty of fish are on the water surface «gasping for air» (i.e. they are consuming oxygen from the thin and oxygenated top layer of water)
  2. When air or gas bubbles are observed in the water
  3. When the pond water is brownish or greyish
  4. When the pond water smells pungent.


What to do when dissolved oxygen is low

Stop loading manure.

Add freshwater into the pond while draining water off the pond bottom.

Stir the pond water by striking the water surface with tree branches or other appropriate materials; row repeatedly across the pond.

Make provisions for flow- through system (if water is readily available).

Use mechanical aerators (if available).

If the water is turbid because of suspended sedimentary particles, spread over the pond surface chopped rice straw or hay, allowing them to settle at the pond bottom together with the silt. But caution: too much decomposing hay can also deplete dissolved oxygen. The pH or hydrogen ion concentration determines whether the water is acidic or alkaline. Highly acidic water (4 or below) can result in fish kills.

What to do when dissolved oxygen is low What to do when dissolved oxygen is low2


Methods to measure pH

Use equipment such as litmus paper, pH meter and water quality measuring kit.

Here is a practical method. Test the water: if water tastes sour, it is acidic. Know the water source; acidic water comes from swamps, bogs or stagnant areas.


What to do if water is acidic

Stop loading manure.

Apply lime.


Ways of knowing the presence of hydrogen sulphide

Hydrogen sulphide is a poisonous gas emitted from the pond bottom as a result of decaying and decomposing organic matter. Its presence is indicated by the following:

Emission of unpleasant odor resembling that of a rotten hard-boiled egg

Presence of dead fish also in the source canal


What to do when hydrogen sulphide occurs

Agitate the pond water.

Add freshwater.

Regulate or stop manure loading.

In serious cases, drain pond and dry pond bottom for 1-2 weeks.


Fish harvesting methods to remove off-flavour

Off-flavour or muddy taste of fish harvested in highly manure-loaded pond and in pellet-fed ponds can be a serious problem if fish farmers do not follow the proper harvesting procedures. People will not buy or eat the fish with off-flavor or muddy taste.

Here are some suggestions to remove the off-flavor or muddy taste:

  1. Stop manure loading or delivery to the fishpond at least two days before harvesting.
  2. Partially drain the pond leaving about 40-50 cm water depth.
  3. Harvest fish by seining before draining the pond totally. This will minimize fish mortality and the murky odor of fish associated with muddy water.
  4. Transfer fish to a net enclosure installed in a pond with clean water or in holding tanks with running water and hold the fish for at least 4-6 hours but preferably for several days.
  5. Sell fish alive or fresh.


Ways to measure water transparency (or turbidity)

Use of a Secchi disk

Use of a Secchi disk
The disk is lowered into the water from a caalibrated rope.
If it disappears within a depth < 30 cm, the water is turbid.

Using one's hand

Using one’s hand
With the hand stretched forward, cup the palm and bend it towards you.
In this position, slowly dip the hand into the water until the palm becomes invisible.
Transparency is expressed as the distance from the wrist to the end of the water mark on the arm.

harvestHarvest1 harvest3



Harvesting and Processing

Pond harvesting can be partial which involves removal of part of the fish stocked from a fish pond and the rest allowed to continue growing. Complete harvesting involves removal of all the fish stocked from the pond.


Equipment required in harvesting fish include, seine nets, scoop nets, clean plastic buckets and baskets, clean source of water and clean fish storage containers.

Once harvested, fish should be handled with care and transported to the market while still fresh.

Where the fish are not destined for immediate sale, simple processing at the farm level can greatly reduce post-harvest losses.


Simple processing would include:

i).       Gutting and scaling

ii).      Sun drying

iii).    Smoking

iv).     Salting

v).      Frying

vi).     Deep freezing

It is important to note that the type of processing will be determined by market preferences.


Diseases and Treatment

There are literally hundreds of afflictions that can affect the health of your fish. The most common maladies seen in home aquaria are usually either bacterial or parasitic in origin. Fungal infections are also sometimes seen, and occasionally physical ailments.

Luckily, most fish ailments are easily diagnosed and can be treated with success. The most common of these afflictions are included here. How to prevent fish disease has steps you can take to reduce the possibility of disease and help to keep disease from spreading if it should occur. A table of contents is provided along with a diagnostic chart with links to appropriate medications.

Understanding how an aquarium and its filtration work to support aquatic life is vital in preventing fish ailments. The basics of life support are the same whether you have a freshwater aquarium, saltwater aquarium, or a mini reef.

How to treat it?


Red Pest

Columnaris – Mouth Fungus



Scale Protrusion

Tail Rot & Fin Rot

Fish Vibriosis


Anchor Worm

Black Spot – Black Ick





Uronema marinum

Velvet or Rust

Marine Velvet

Brooklynella/Clownfish Disease



Ich – White Spot

Marine Ich – Crypt/Marine White Spot

Neon Tetra Disease

Glugea and Henneguya


African Bloat ‘Malawi Bloat’




Congenital Abnormalities



LymphocystisHead and Lateral Line Erosion
‘Hole-in-the-head’ DiseaseEye ProblemsSwim-bladder Disease


Types of Fish Disease

Fish ailments can be separated into 4 general types including bacterial infections, fungal infections, parasitic or protozoan infections, and physical ailments and wounds.

Bacterial Diseases: Bacterial diseases are usually characterized by red streaks or spots and/or swelling of the abdomen or eye. These are best treated by antibiotics such as penicillin, amoxicillin, or erythromycin.


Fungal Diseases

Common fungal infections often look like gray or white fluffy patches. are

Parasitic Diseases: The most common parasitic disease called “Ich” can be treated most effectively with copper or malachite green in the right dosage. Most treatments will have copper as an ingredient. Many water treatments like “Aquari-Sol” will also contain copper as an ingredient. If the treatment you use is an anti-biotic or copper based, remember to remove all carbon from the filtration system.

Physical Ailments: Physical Ailments are often the result of the environment. Poor quality water conditions can lead to fish gasping, not eating, jumping out of the tank, and more. Tank mate problems can result in nipped fins and bite wounds.

How to Prevent Fish Diseases: Some steps can be taken to reduce the possibility of your fish getting a disease. Following these precautions can also help keep fish diseases from spreading if they do occur.

  • Buy only good-quality, compatible fish.
  • Quarantine new fish before adding them to the aquarium. (A hospital tank can be used for this).
  • Avoid stressing the fish with rough handling, sudden changes in conditions, or “bully” tankmates.
  • Don’t overfeed your fish.
  • Remove sick fish to a hospital tank for treatment.
  • Disinfect nets used to move sick fish.
  • Don’t transfer water from the quarantine tank to the main aquarium.
  • Don’t let any metal come in contact with the aquarium water.

Anti-biotics: When using any anti-biotic, make sure the biological filtration in your aquarium is not destroyed. You want to be certain the treatment does not kill the nitrifying bacteria in your system at the same time it attacks harmful bacteria on your fish. Although most of the treatments available at the store state that they will not harm your biological filter, sometimes they will. It is best to either monitor your ammonia and nitrite levels, or use an ammonia remover such as “AmQuel” to be sure your levels of ammonia don’t become a problem.
Copper Treatments: When using any medication which has copper as an ingredient, be aware that most plants will not do as well. Invertebrates, such as snails, can also be killed if the amount of copper is sufficient.  Indeed, most snail removers are copper based.


Diagnostic Chart

If you notice something is wrong with your fish, a proper diagnosis is usually all you need to worry about. In most cases, a proprietary treatment (fish medications) purchased at a pet store will work very well.

Steps to diagnosing and treating your fish:

Symptom: Match the symptoms your fish is showing with those listed under the ‘Symptom’ column.

Possible Cause: Learn about each disease by clicking on the link under ‘Possible Cause’.

Medication: Find the treatment for the disease under the ‘Medication’ column.

Product Link: Use the ‘Compare Prices’ column to compare similar products and merchant’s prices.

SymptomPossible CauseMedication
Small white spots on fins / skin, clamped finsIchCoppersafe, Quick-Cure
Ich-Ease, Aquari-sol, Cure-Ick, Super Ick Cure
Ick Medication
Ick Medications
Peppery coating, yellowish, clamped finsVelvetCoppersafe, Quick-Cure
Aquari-sol, Cure-Ick, Super Ick Cure
Gray or white fluffy patchesFungusMaracyn, Fungus Cure, Methyl Blue, Antibiotics for secondary infections.Fungus Cure
Fungus Cure
Gray or white fluffy patches around mouthColumnaris, Mouth FungusErythromycin, Kanacyn, Fish Pen (penicillin), Maracyn
Antibiotics for secondary infections. (Use Maracyn simultaneously with Maracyn II)
Fish Antibiotics
Fish Antibiotics
Pale appearanceNeon Tetra diseaseNo Known Cure
Unusual racing around tank.
Black to red nodules beneath skin.
FlukesParagon, Clout, Proxipro, Fluke-TabsFish Flukes
Fish Flukes
Milky cloudiness on skinCostiaChilodonellaCoppersafe,  Quick-Cure, AcriflavineFish Antibiotics2
Fish Antibiotics
Destruction of fins or tailTail or fin rotMaracyn, Methylblue, Organi-Cure, Antibiotics, Tetracycline, ChloromycetinTail Rot Fin Rot Medication
Tail Rot / Fin Rot Medication
Red streaks on bodyRed pestFin rotTetracycline, Penicillin. Acriflavine, Chloromycetin, Fish Pen (penicillin)Fish Antibiotics
Fish Antibiotics
Yellow to black nodules on skinIchthyosporidium
Ulcerated patches on skinRed pestIchthyosporidium
Emaciation, hollow belly, possibly soresTuberculosisNo Known Cure
Protrusion of scales with bloated bodyDropsyFeed Anti-Bacteria medicated foodAnti-Bacteria Medicated Foods
Anti-Bacteria Medicated Foods
Protrusion of scales, body normalScale protrusion
Eyes protrudePop eyePenicillin or amoxicillinFish Antibiotics
Fish Antibiotics
Cloudiness of eyesEye problems,
Maracyn, Maracyn Plus, Antibiotics for bacterial infection, Increase vitamin A.Bacterial Antibiotics
Bacterial Antibiotics
Hole in head, ulceration of lateral line, loss of appetiteHead and Lateral Line Disease
Paragon, Hole N Head Guard, Hakari Hole in the HeadHole in the Head Medications
Hole in the Head Medications
 White slimy feces, loss of appetite, swim backwardsHexamitaMetronidazoleHexamita Medications
Hexamita Medications
Crustaceans on skinArgulusErgasilusParagon, Trifon, Anti-Fluke treatmentAnti-Fluke treatments
Anti-Fluke treatments
Flukes on skin or gillsFlukes
Worms hanging from anusNematodaParagon, Trifon, Worm Parasitic treatmentWorm Parasitic treatment
Worm Parasitic treatment
Heart shaped wormsLeeches
Nodular white swellings on fins or bodyLymphocystisGlugeaHenneguyaNo Known Cure. Since lymphocystis is not harmful and will drop off after some time, no cure is necessary.
Glancing off rocks or plantsVelvetIchFlukes,Anchor wormChilodonellaCostiaIch Medication (Ich)
Paragon (Worms)
Ick and Worm Medications
Ick and Worm Medications
Severe loss of balanceSwim bladder diseaseCheck aquarium parameters, look for signs of other disease.
Gasping at surfaceOxygen/ O2 deficiency, CO2 excess, tank too hot, toxins, shockOxygenex, Oxygen stones – (short-term).
Provide better water circulation, lower temperature
Oxygen Aquarium Aids
Oxygen Aquarium Aids
Jumping out of waterpH wrong, toxinsCheck for ph extremes, do water changes with dechlorinated water.Ph Buffers
Ph Buffers

Automatically set & stabilize your aquarium pH . Remove chlorine & detoxify heavy metals.
Appetite dwindles, belly swells, feces trailsConstipation or Internal ParasitesMedicinal parrafin oil, change in diet,
Anti-Parasitic Medicated Food
Anti-Parasitic Medicated Foods
Anti-Parasitic Medicated Foods
Fins frayed or split, scales missingInjuriesWound Treat, Bio Bandage, Stress relievers.
Look for and remove bully fish.
Medications: Melafix
Wound Treatments
Wound Treatments


Bacterial Diseases

Red Pest

Symptoms: Bloody streaks on fins or body.

Red Pest is called such because of bloody streaks that appear on the body, fins and/or tail. These streaks could proceed to ulcerations and possibly lead to fin and tail rot with, in severe cases, the tail and/or fins falling off. As the disease is internal, external treatments are usually not effective, except in very slight cases. In slight cases, treat the aquarium with a disinfectant and clean the aquarium as best as possible. Do not feed a lot while the aquarium is being treated. To disinfect, use acriflavine (trypaflavine) or monacrin (monoaminoacridine) using a 0.2% solution at the rate of 1 ml per liter. Both disinfectants will color the water, but the color disappears as the disinfectants dissipates. If the fish do not appear to respond favorably, discontinue disinfections, then add an antibiotic to the food. With flake food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. If added to 25 grams of flake food, one capsule should be enough to treat dozens of fish. A good antibiotic is chloromycetin (chloramphenicol). Or use tetracycline. If you feed your fish frozen foods or chopped foods, try to use the same ratio with mixing. As a last resort add at most 10 mg per

liter of water.


Columnaris – Mouth Fungus
Symptoms: cottony patches around the mouth, White spots on mouth, around the chin and mouth area, edges of scales and fins, cottony patches around the mouth. May be accompanied by clear stringy feces, a loss of appetite, and rapid gilling where gills are infected.

Names Columnaris is known by are Mouth Fungus, Cotton-Wool, Cotton-Mouth, Mouth-Rot, Saddle Back,  Flexibacter, False Neon Disease, and Guppy Disease. It is often called Mouth Fungus because it looks like a fungus attack of the mouth. It is actually caused from the bacterium Flavobacterium columnare, previously called Flexibacter columnarisBacillus columnarisChondrococcus columnaris, and Cytophaga columnaris. This is a common bacterial infection that affects freshwater aquarium fish, particularly livebearing fish and catfish. It is not seen in marine fish, they can be infected by myxobacterial diseases that are similar to columnaris, yet this is very uncommon in the aquarium.

Columnaris can enter the fish through the gills, mouth, or small wounds on the skin and results in an internal or external infection. It can have either a chronic progression of days or months or an acute progression with lesions spreading quickly, often wiping out whole populations of fish in just a few hours. It is highly contagious and may be spread through contaminated nets, specimen containers, and even food.
This disease is brought on by stress, injury, inadequate diet, and poor water quality, including an unstable pH. To prevent Columnaris maintain your water with good biological filtration and weekly water changes that include vacuuming the substrate. Keep the tank well aerated, provide your fish with a varied diet, and don’t overstock. Columnaris generally shows up first as a gray or white line around the lips and later as short tufts sprouting from the mouth like fungus. This bacterium produces protein and cartilage degrading enzymes that eat away at the fish and forms round or oval shapes with an open ulcer in the center. It may affect the fins, beginning with degradation at the edges, or as a lesion near the dorsal fin. The “saddleback” condition is a discolored gray patchy area near the dorsal fin and a pale white band encircling the body of the fish. A yellowish-brown ulcer develops in the center as it progresses. This coloring is caused by detritus particles trapped in the slime produced by the bacteria.
This is a quick acting disease and needs immediate treatment. The toxins produced and the inability to eat will be fatal unless treated at an early stage. This bacteria is often accompanied by a second infection of an Aeromonas bacteria and fungus often invades the affected skin. Be aware that some strains of this bacteria are becoming resistant to antibiotics. So ensure you treat for the full length of the medication. To rid the aquarium and fish of this disease, first increase the water quality and then begin treatment.

You can treat Columnaris with a gram-negative medication. However, other bacteria that are gram positive mimic the Columnaris Disease, so if you use a gram positive treatment and it worked, the affliction was NOT Columnaris disease. Some aquarists suggest using both the gram positive and negative together just in case you are not sure. Several types of antibiotics and medications can be used to treat Columnaris:


Penicillin: Penicillin at 10,000 units per liter is a very effective treatment. Treat with a second dose in two days.


Chloromycetin: You can use chloromycetin, 10 to 20 mg per liter, with a second dose in two days.

Kanacyn (kanamycin): Kanacyn will treat both bacteria at once.

Maracyn (erythromycin): Maracyn is effective against Columnaris, and using Maracyn 2 (minocycline) in conjunction with it will treat the Aeromonas bacteria as well.

Others: Copper sulphate, Furan, Tetracycline, and Potassium permanganate. Nifurpirinol, Acriflavine, Chloramphenicol and Malachite green are also said to be effective.

Medicated Foods: Feeding food dosed with Terramycin (Oxytetracycline) will help to internally treat this disease.


Tuberculos – Mycobacteriosis
Symptoms: fish tuberculosis, piscine tuberculosis, acid-fast disease, granuloma disease.
Symptoms: Emaciation, hollow belly, possibly sores.

Tuberculosis is caused by the bacterium Mycobacterium piscium. Fish infected with tuberculosis may become lethargic, hollow bellied, pale, show skin ulcers and frayed fins, have fin and scale loss, and loss of appetite. Yellowish or darker nodules may appear on the eyes or body and may deform the fish. The main causes for this disease appears to be overcrowding in unkempt conditions; ie. poor water quality. All fish species could be susceptible though some are more susceptible than others. Those most susceptible are the labyrinth air breathers like the Gouramis, Bettas, and Paradise Fish. Others include Neon Tetras, Discus, and the Ram Cichlid.

There is no absolute treatment. However, the most effective treatment known for this disease is to treat with Kanamycin and Vitamin B-6 for 30 days. Kanamycin can be purchased at your local fish store. Liquid baby vitamins work well as s Vitamin B-6 source. They are available at your local pharmacy. Add one drop per every 5 gallons of aquarium water during treatment.

If the treatment is ineffective, the best thing to do is destroy the infected fish.

If either unkempt conditions or overcrowding are the suspected cause, correct the condition. It is possible for humans to contract this disease so we recommend using caution when dealing with it. Humans are very rarely are at risk from aquariums though. It is more common to contract this disease from public swimming areas or as a food contaminant.


Symptoms: Bloating of the body, protruding scales.

Dropsy is caused from a bacterial infection of the kidneys, causing fluid accumulation or renal failure. The fluids in the body build up and cause the fish to bloat up and the scales to protrude. It appears to only cause trouble in weakened fish and possibly from unkempt aquarium conditions.
An effective treatment is to add an antibiotic to the food. With flake food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. If added to 25 grams of flake food, one capsule should be enough to treat dozens of fish. A good antibiotic is chloromycetin (chloramphenicol). Or use tetracycline. If you feed your fish frozen foods or chopped foods, try to use the same ratio with mixing. As a last resort add at most 10 mg per liter of water. Also, if unkempt conditions are the suspected cause, correct it.

Scale Protrusion
Symptoms: Protruding scales without body bloat.

Scale protrusion is essentially a bacterial infection of the scales and/or body. A variety of bacterium could be the culprit here, as can unkempt aquarium conditions. An effective treatment is to add an antibiotic to the food. With flake food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. If added to 25 grams of flake food, one capsule should be enough to treat dozens of fish. A good antibiotic is chloromycetin (chloramphenicol). Or use tetracycline. If you feed your fish frozen foods or chopped foods, try to use the same ratio with mixing. As a last resort add at most 10 mg per liter of water. Also, if unkempt conditions are the suspected cause, correct it.

Tail Rot & Fin Rot
Symptoms: Disintegrating fins that may be reduced to stumps, exposed fin rays, blood on edges of fins, reddened areas at base of fins, skin ulcers with gray or red margins, cloudy eyes.

Tail and fin rot appears to be a bacterial infection of the tail and/or fins and may be caused by generally poor conditions, bully, or fin nipping tankmates. If aquarium conditions are not good an infection can be caused from a simple injury to the fins/tail. Tuberculosis can lead to tail and fin rot. Basically, the tail and/or fins become frayed or lose color. Over time the affected area slowly breaks down.

First, attempt to ascertain the cause. Then treat accordingly. Also, treat the water or fish with antibiotics. If added to the water, use 20 – 30 mg per liter. If the fish is to be treated add an antibiotic to the food. With flake food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. If added to 25 grams of flake food, one capsule should be enough to treat dozens of fish. A good antibiotic is chloromycetin (chloramphenicol) or tetracycline. If you feed your fish frozen foods or chopped foods, try to use the same ratio with mixing. As a last resort add at most 10 mg per liter of water. Also, if unkempt conditions are the suspected cause, correct it.


Fish Vibriosis
Symptoms: Lethargy, increased respiration, loss of appetite, skin hemorrhages, and death.

Vibrio is a genus of Gram-negative bacteria found primarily in saltwater or brackish water, and consisting of 70 or more strains. Fish Vibriosis involves a variety of infectious strains of Vibrio bacteria, most notably Vibrio anguillarumV. ordaliiV. damsela, and V. salmonicida.

Fish Vibriosis occurs most often in marine animals or brackish water fish, though it can occasionally be found in tropical species. Fish contract the bacteria through open sores or feeding on dead fish that died from the disease. Hemorrhaging starts with reddening or blood streaks under the skin surface, becoming red spots on the ventral and lateral areas of the fish. Swollen dark lesions develop, turning into ulcers and release bloody pus. There may also be eye problems with cloudy eye, which can lead to pop-eye and eye loss.

The course of a vibriosis infection in fish is usually very rapid. Most infected fish die without showing more visual signs than the ulcers, and sometimes death may occur suddenly before any signs are noticed at all.

The best treatment includes oral antibiotics. Kanamycin is one of the best, also chloramphenicol or furazolidone are good. When treating with antibiotics, it must be done in a quarantine tank rather than the main aquarium. This is because antibiotics will damage the biological filter in the main tank, throwing the nitrification cycle into reverse and cause a spike in nitrites and ammonia after just a few days.

A word of caution: People can become infected by Vibrio bacteria when handling infected fish. Hence the nicknames of “fish handler’s disease” and “aquarium handler’s disease”. People can become infected when water containing the bacteria comes into contact with cuts or open sores on the skin. The bacteria may be in swimming pools, aquariums, or coastal waters.

Vibrio infections are very rare in the United States. Cholera is probably the most well-known illness caused by one of the vibrio bacteria. People sick with cholera usually have intestinal symptoms such as diarrhoea and vomiting. Those with compromised immune systems can be at higher risk, even death, with some strains of Vibrio bacteria.


Protozoan Diseases

Velvet, Rust – Gold Dust Disease (this is either Oodinium pilularis or Oodinium limneticum)
Symptoms: Peppery coating giving a yellow to light brown “dust” on body, clamped fins, respiratory distress (breathing hard as seen as frequent or quick gill movements), cloudiness of eyes, and glancing off decor or substrate, possible weight loss.

Velvet disease in freshwater fish is caused by either Oodinium pilularis or Oodinium limneticum, which are parasitic skin flagellates. This parasite swims in the aquarium until it finds a fish host and adheres to it.

In Oodinium pilularis (as well as with “Ich” Ichthyophthirius multifiliis) it eats into the cells of the epithelial layer of the skin and fins as well as through the mucous membrane in the mouth. The mature parasite then leaves the host and drops to the bottom of the aquarium or plants. It then forms a cyst that divides, forming between 34 – 64 new cells, then bursts freeing the new cells into the aquarium to find a fish host.

Oodinium limneticum is similar, but attacks the fish’s skin and fins rather than burrowing under the epithelial layer, so it is localized right on the surface. It also multiplies on the host rather than at the bottom of the aquarium or on the plants.

This disease has the appearance of a golden or brownish dust over the fins and body. The fish may show signs of irritation, like glancing off aquarium decor, shortage of breath (fish-wise), and clamping of the fins. The gills are usually the first thing affected. Velvet affects different species in different ways. Danios seem to be the most susceptible, but often show no discomfort. This disease is highly contagious and fatal.

They can be treated either in the separate or in the main tan. A good treatment is with copper sulphate at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary. Aquarisol is one medication of this sort that is usually readily available at pet stores. Acriflavine (trypaflavine) may be used instead at 0.2% solution (1 ml per liter). There are things to be aware of with each of these treatments however. Acriflavine can possibly sterilize fish and copper can lead to poisoning, so the water should be gradually changed after a cure has been effected.


Marine Velvet – Velvet Disease (Oodinium ocellatum)
(Syn: Amyloodinium ocellatum or Branchiophilus maris). Also called Coral Reef Fish Disease.
Symptoms: White, yellow to light brown, or grey “dusty” appearance on body, respiratory distress (fast breathing – gills opening more than 80 times per minute), loss of appetite, rubbing or scratching against decor or substrate.

Marine velvet is one of the most common maladies experienced in the marine aquarium, with the other being Marine Ich. It is found in all the oceans of the world and often infects wild and newly caught marine fish. Velvet disease in saltwater fish is caused by Oodinium ocellatum, (syn: Amyloodinium ocellatum or Branchiophilus maris), which is a parasitic skin flagellate. It is a fast moving disease that can cause mass casualties. Primarily it infects the gills of fish but can attach itself to the body as well, burrowing deep into the skin’s subcutaneous layer. Deaths are generally a result of interference to the respiratory system. This disease is highly contagious and fatal.

Chemical treatments for this disease include using copper (copper sulphate). Follow the instructions provided by the manufacturer. Generally, it involves maintaining copper levels between .12 to .18 mg/L for 21 days, and using a quarantine tank is best. Natural methods include hyposalinity in a quarantine tank with a low salinity, by lowering salt level to around 1.009 – 1.010 for 10 days. A danger with with using low salinity is in re-acclimating the fish to a higher salinity. You must be able to accurately measure the salinity and must increase it very slowly.


Brooklynellosis – Clownfish Disease (Brooklynella hostilis)
Symptoms: loss of appetite, develops lesions on the body, sloughing off excessing body slime, heavy respiration/gasping for oxygen,constantly scratches against the substrate.

Brooklynellosis is caused by a protozoan parasite called Brooklynella hostilis. This protozoan disease is mostly associated with clownfish, although other fish can contract it. This quick killer is a parasite that infests the gills and skin, where the fish develops lesions on the body, sloughing off excessing body slime and constantly scratches against the substrate. The infesting of the gills causes them heavy respiration as they gasp for oxygen. The fish will succumb to this disease in about 30 hours after the infection is identified. The first sign is a lack of appetite. Some newer strains of White Spot Disease or Crypt look similar to Brooklynella.

Formalin and Malachite green are two active ingredients found in medications that have been used to treat this infection. One is a dip with 10 times the dose and one is as directed on the bottle to treat the entire quarantine tank. Hyposalinity which is 1.009 for the duration of treatment along Formalin is recommended. Copper has no affect on Brooklynella.


Symptoms: Milky cloudiness on skin.

This is a rare protozoan disease that causes a cloudiness of the skin. The best treatment is with copper at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary. Acriflavine (trypaflavine) may be used instead at 0.2% solution (1 ml per liter). As acriflavine can possibly sterilize fish and copper can lead to poisoning, the water should be gradually changed after a

cure has been effected. Raising the water temperature to 80° – 83° F for a few days has also been effective.


Symptoms: The first symptom of slimy, white mucous feces, even while still eating and acting normal. Further signs are the fish hiding in the corner with it’s head down, the head above the eyes gets thin, they blacken in color, and swim backwards.

Hexamita are intestinal flagellated protozoa that attack the lower intestine. Discus and other large cichlids, especially Oscars, are especially prone to Hexamita. Saltwater fish are affected on rare occasions as well As it is a disease of the digestive tract, a wasting away or loss of appetite may be experienced.

An effective treatment is the drug metronidazole. Metronidazole is an antibiotic for anaerobic bacteria with anti-protozoal properties. This drug is reef safe, and medications are either added to the water or mixed with the fish food. Metronidazole works by ceasing the growth of bacteria and protozoa. Metronidazole is an antibiotic for anaerobic bacteria with anti-protozoal properties, and this drug is reef safe. Some available products that contain metronidazole include Seachem Metronidazole, Seachem AquaZole, Thomas Laboratories’ Fish Zole and National Fish Pharmaceutical’s Metro-Pro. A combined treatment in the food (1% in any food the fish will eat) and in the water (12 mg per liter) is recommended. Repeat the water treatment every other day for three treatments. And effective treatment is with Seachem’s Metronidazole.

(This disease is often confused with another disease called Head and Lateral Line Erosion (HLLE), which use to be called “hole-in-the-head” disease, because both these diseases are often seen simultaneously in the same fish. Head and Lateral Line Erosion disease looks like cavities or pits on the head and face. This is not a protozoan disease, but is actually caused by environmental conditions.).


Ich – Ick – White Spot Disease (Ichthyophthirius multifiliis)
Symptoms: Salt-like specks on the body/fins.  Excessive slime. Problems breathing (ich invades the gills), clamped fins, loss of appetite.

Ich, Ick, or White Spot Disease is the most common malady experienced in the home aquarium. Luckily, this disease is also easily cured if caught in time! Ich is actually a protozoa called Ichthyophthirius multifiliis. There are three phases to the life cycle of this protozoa. Normally, to the amateur aquarist, the life cycle is of no importance. However, since Ich is susceptible to treatment at only one stage of the life cycle, an awareness of the life cycle is important.

Adult phase – it is embedded in the skin or gills of the fish, causing irritation (with the fish showing signs of irritation) and the appearance of small white nodules. As the parasite grows it feeds on red blood cells and skin cells. After a few days it bores itself out of the fish and falls to the bottom of the aquarium.

Cyst phase – after falling to the bottom, the adult parasite forms into a cyst with rapid cell divisions occurring.

Free swimming phase – after the cyst phase, about 1000 free swimming young swim upwards looking for a host. If a host is not found within 2 to 3 days, the parasite dies. Once a host is found the whole cycle begins anew.

These three phases take about 4 weeks at 70° F but only 5 days at 80° F. For this reason it is recommended that the aquarium water be raised to about 80° for the duration of the treatment. If the fish can stand it, raise the temperature even higher up to 85°.

The free swimming phase is the best time to treat with chemicals. Raising the aquarium temperature to 80° F will greatly shorten the time for the free swimming phase to occur. The drug of choice is quinine hydrochloride at 30 mg per liter (1 in 30,000). Quinine sulphate can be used if the hydrochloride is not available. The water may cloud but this will disappear. By reducing the time (with raised temperature) of the phases, you should be able to attack the free swimming phase effectively.

Some aquarists like to use malachite green, but it tends to stain the plastic and silicone in the aquarium. Most commercial remedies contain malachite green and/or copper, which are both effective.

Marine Ich – Crypt – Marine White Spot Disease (Cryptocaryon irritans)
Symptoms: Small white spots, nodules, or patches on their fins, body, or gills. Fish may produce excessive slime, show problems breathing (ich invades the gills), have frayed fins, loss of appetite, and cloudy eyes. White spots may not be obvious on light coloured fish or if the infection is just in the gills, however that may not rule out infection. Other indications can include rubbing or scratching against decor or substrate, abnormal swimming, hanging at the surface or on the bottom, acting lethargic, or breathing more rapidly as if in distress.

Marine Ich, Crypt, or Marine White Spot Disease is one of the most common maladies experienced in the marine aquarium, with the other being Marine Velvet. It can grow in environments with excessive stress, poor water quality and fluctuations in water temperature. It can also come into the aquarium on a new fish that is a carrier. These protozoa have four phases to its life, lasting up to 38 days depending on the temperature of the environment. This parasite affects marine and brackish fish. Aquarists are most familiar with the stage where the protozoa is infesting the host, with small white spots on the fish’s body and fins. Unfortunately, this visual clue is also the reason for difficulty in eradicating marine ich. Once the parasite has left the host’s body many aquarists believe their fish is cured and the problem is solved and so they cease treatment, only to have another larger reoccurrence.

For eradication treatment must be carried through to completion, so understanding the parasite’s life cycle will greatly increase your chances of success. The life cycle is outlined here:

Trophont phase – when the parasite is growing in the skin or gills of the fish it appears as small white nodules, and the fish begins showing signs of irritation. It will spend 5 to 7 days (depending on the temperature) feeding on the fish. Once it reaches maturity it leaves the fish, reportedly after the lights go out. It is now called a protomont.

Protomont phase – the protomont will free swim or will crawl about the substrate for several hours (2 to 18 hours) producing a sticky wall around itself with which it is able to adhere to a surface. Once it adheres it begins to turn into a cyst and is now called a tomont.

Tomont phase – at this stage there is rapid cell divisions occurring, resulting in hundreds of daughter parasites that are called tomites. This stage can last anywhere from 3 to 28 days. Eventually the tomites hatch and begin swimming about looking for a host and are now called theronts.

Theront phase – newly hatched, they are swimming about looking for a host which they must find within 24 hours or they will die. Once a host is found they turn into trophonts and the whole cycle begins anew.

The life cycle of this parasite can vary dramatically and is dependent on temperature. Optimal growth of most strains of Cryptocaryon appear to be about 73.4–86°F (23–30°C), and they cycle faster in a warmer environment. A common mistake is to confuse the treatment of this protozoan with the treatment for freshwater Ich (Ichthyophthirius multifiliis). Raising the temperature of the tank does not eliminate this protozoa like it does with freshwater Ich.
Ideally the parasite would be eliminated while on the host or shortly after leaving the host. However, those that are buried in the gills are immune to treatment until they leave the fish. This along with the variability of the cycle makes it difficult to treat in such a timely manner.
To rid the aquarium of this protozoa, it is recommended that you use a combination of water changes and chemical treatment, a multiple number of times.  A common mistake is to confuse the treatment of this protozoan with the treatment for freshwater Ich (Ichthyophthirius multifiliis). Raising the temperature of the tank does not eliminate this protozoa like it does with freshwater Ich.


Chemical Treatments
Chemical treatments for this disease include using copper, formalin, or a combination of copper and formalin. Follow the instructions provided by the manufacturer. Achilles Tangs are sensitive to cooper based products so use them carefully. Equally effective is a (normal saltwater) short “dip” with Formalin (see directions on bottle for the dip) for these patients, and remove them to a separate tank.


Natural Treatments:
Natural methods include either a quarantine tank with a low salinity (hyposalinity), dips, or large frequent water changes.
Low Salinity Method: For low salinity keep the specific gravity of the water at approximately 1.009-1.010 with temperatures of 78 – 80° F (25 – 27° C) for 14 days. A problem with this method are that lower salinities are not as easily tolerated by many common tropical marine species, including angelfish and deep water fish. These types of fish have a much shorter time that they can tolerate the lower salinity. A danger with with using low salinity is in re-acclimating the fish to a higher salinity. You must be able to accurately measure the salinity and must increase it very slowly.
Dip Method: Using freshwater or or lower salinity dips, either with a duration of just a few minutes, or short to prolonged immersion baths (duration in hours to days) can be used for tolerant fish to kill or reduce the numbers of external parasites on the fish. Unfortunately trophonts and tomonts are more protected, so longer dips and baths are needed than for other parasite species.
Water Change Method: For the water change method, replace 50% of the aquarium water daily for 14 days. This is perfectly safe method as long as temperature and salinity are the same, and this will remove the parasites while in a free swimming stage. Reportably some healthy fish can develop a limited immunity. It may not be a total immunity, rather being just a small amount of infestation rather than extensive infestation. This immunity is short-lived lasting only about six months.

Neon Tetra Disease
Symptoms: Whitened areas deep into the fishes’ flesh. Muscle degeneration leading to abnormal swimming movements.

So named for the fish it was first recognized on, the Neon Tetra. It is caused by the sporozoa Plistophora hyphessobryconis. Even though it is named after Neon Tetras, it can appear on other fish. Whitish patches appear as if just below the skin. In Neon Tetras it destroys the bright blue-green neon stripe. The organisms form cysts which burst and release spores. The spores penetrate further and form more cysts. Eventually, the spores migrate to the water and are eaten by other fish in the food. These spores migrate into the digestive tract, then the muscles, and a new infection starts. There is no known cure. It is best to destroy the infected fish and clean the aquarium.

Glugea and Henneguya

Symptoms: Similar to Lymphocystis, the fish will have nodular white swellings on fins or body.

Glugea and Henneguya are sporozoans that form large cysts on the fish’s body and release spores. Luckily, these diseases are very rare. The fish bloat up, with tumor like protrusions, and eventually die. No cure, as of yet. It is best to destroy the infected fish before the spores can spread.

Symptoms: Dulling of the colors due to excessive slime, fraying of the fins, weakness, gill damage 
This disease causes a blue white cloudiness on the skin and attacks the gills. Later the skin may be broken down and the gills destroyed. The fish may behave like they have irritations, by glancing off aquarium decor, they may have clamped fins and difficulty breathing.
Acriflavine (trypaflavine) may be used at 1% solution (5 ml per liter). As acriflavine can sterilize fish, the water should be gradually changed after a cure has been effected. It also helps to raise the temperature to about 80° F.


African Bloat – “Malawi Bloat”

Symptoms: The first sign of ‘bloat’ is loss of appetite which is then followed by swelling of the abdomen, labored breathing, listlessness, reclusiveness, possible red striations on the body, and stringy white feces.

There seems to be no explainable rationale as to its cause of bloat. Once a fish becomes afflicted it is often fatal. A fish that is not eating must be treated immediately or it can quickly become incurable and die. Though It is not certain what this disease is, it is generally believed to be caused by a protozoal parasite complicated by bacterial infection. Bloat is a serious malady often associated with African cichlids especially those from Lake Malawi, thus the common name ‘Malawi Bloat’. The Tropheus species from Lake Tanganyika are also very susceptible.

The most common cause of this disease is stress and the first sign if illness is not eating. Stress can be caused by such things as transport, netting, poor water quality, insufficient diet, over feeding, and a lack of hiding places. Other causes, that are easily remedied, are an improper diet and adding too much salt to the water. Prevention is of utmost importance, and It is possibly to cure a fish if treated right away.

Following are some techniques aquarists use:

Any new specimens you obtain can have bloat or will often soon develop it. When you first acquire them try to provide them with the same food that the dealer was feeding, and then wean them onto a good vegetable based diet; Spirulina flake and pellet. Some will soak the food in dissolved metronidazol and feed them that for the first few days when first obtained. Seachem makes a metronidazol that can be bound to food when used with their Focus product. A good vegetable based diet is important.

A healthy group of fish will eat with gusto. But even though they can be very active feeders it is important to not overfeed them. Keep an eye on them, and if one is not eating with vigor some aquarists will then treat the tank with Clout.

One author says that they will segregate an ailing fish the second they see signs of not eating, and then will do water changes every day for 5 days in the main aquarium. Metronidazol is considered the most reliable cure and some use Clout as another cure, but do not use them together.


Parasitic Diseases

Fish louse (Argulus)
Symptoms: The fish scrapes itself against objects, clamped fins, visible parasites about 1/4 inch in diameter are visible on the body of the fish.

The fish louse is a flattened mite-like crustacean about 5 mm long that attaches itself to the body of fish. They irritate the host fish which may have clamped fins, become restless, and may show inflamed areas where the lice have been. With larger fish and light infestations, the lice can be picked off with a pair of forceps. Other cases can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.

Anchor Worm (Lernaea)
Symptoms: The fish scrapes itself against objects, whitish-green threads hang out of the fish’s skin with an inflamed area at the point of attachment.

Anchor worms are actually crustaceans. The young are free swimming and borrow into the skin, go into the muscles and develop for several months before showing. They release eggs and die. The holes left behind are ugly and may become infected.
The anchor worm is too deeply imbedded to safely remove. Treatment can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.


Black Spot – Black Ick (diplopstomiasis)
Symptoms: The fish, very irritated, scrapes itself against objects, appears as small black specks or smudges on the body and around the mouth, and if heavily infected may experience blood loss.

Black Spot or Black Ick is rare in aquariums. It is generally seen in outdoor ponds, especially those with mud bottoms, but it can be introduced when adding new fish into the aquarium. Fish that are most readily susceptible are the Silver Dollar, Piranha, or other fish of these types. In general, it does relatively little damage to the fish, even if they are heavily infested.

The disease is caused by a parasite (larval trematode) that burrows into the skin of a fish where it forms a cyst that is about one millimetre in diameter. It has a complex life cycle that in order to survive, requires fish eating birds or animals, snails, or fish at different stages infected with the disease. Black Spot is generally easy to cure. Either treat with salt baths or there are a number of commercially available treatments and preventatives.

Symptoms: The fish scrapes itself against objects, whitish-green threads hang out of the fish’s gills.

This parasite is like the anchor worm, but is smaller and attacks the gills instead of the skin. Treatment can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.


Symptoms: The fish scrapes itself against objects, rapid gill movement, mucus covering the gills or body, the gills or fins may be eaten away, the skin may become reddened.

There are many species of flukes, which are flatworms about 1 mm long, and several symptoms that are visible. They infest gills and skin much like ich, but the difference can be seen with a hand lens. You should be able to see movement and possibly eye spots, which is not found in ich. Gill flukes will eventually destroy the gills thus killing the fish. Symptoms of a heavy infestations are pale fish with drooping fins, rapid respiration, glancing off aquarium decor, and /or hollow bellies.

Treatment can best be done with a 10 to 30 minute bath in 10 mg per liter of potassium permanganate. Or treat the whole tank with 2 mg per liter, but this method is messy and dyes the water.


Symptoms: Worms hanging from the anus.

Nematodes (threadworms) infect just about anywhere in the body but only shows itself when they hang out of the anus. A heavy infestation causes hollow bellies. Lighter infestations usually cause no problems with the fish. Short of destroying the fish, which is easier, two treatments have been suggested. First treatment; soak the food in parachlorometaxylenol and give the fish a bath or treat the aquarium with 10 ml per liter. The bath should last for several days. Second treatment; find special food containing thiabendazole as a nematode (threadworm) cure and hope the fish will eat it.


Symptoms: Leeches are visible on the fish’s skin.

Leeches are external parasites and affix themselves on the body, fins, or gills of the fish. Usually they appear as heart shaped worms (they are just curled up) attached to the fish. They are usually introduced to the aquarium via plants or snails. Since leeches are sucking and borrowing into the surface of the fish, removal with forceps can cause great damage, if not death, to the fish. If the fish is bathed in a 2.5 percent solution of salt for 15 minutes, most of the leeches should just fall off. Those that do not will be affected enough to remove with forceps with minimal damage. Another treatment is to add Trichlorofon at 0.25 mg/l to the aquarium. Live plants should be removed and treated with potassium permanganate at 5 mg/l before replanting.

Uronema marinum
Symptoms: Skin scraping, pale discoloration, loss of colour, weight loss, dehydration, flashing, and rapid breathing.

The saltwater parasite, Uronema marinum, is a free-living ciliated protozoa that can cause fatal infections in marine fish. It is an opportunistic feeder that normally eats on bacteria, but when the immunization of a fish is low it will attack, invading the fish’s muscles and internal organs. This infestation is often the result of the introduction of a new fish, overcrowding, and poor water quality resulting from a high organic load in the aquarium.
This parasite is difficult to identify as the symptoms can also be indicative of other parasitic and bacterial problems. However, it can be debilitating and ultimately fatal to a variety of marine fish including Tangs, especially the Yellow Tang, Angelfish species especially those in the genus Centropyges, Seahorses, many species of Butterflyfish, yellow headed Jawfish, and others.

The best way to avoid the problem is to keep your current tank free from infestation. Quarantine all new fish for a period of three weeks, improve the water quality of the tank, and reduce the stress level in the aquarium by reducing the number of fish and incorporating places for fish to hide and rest.

There are several types of medications that can be used to treat infected fish:

Medications such as Malachite green, Copper Sulfate, or Methylene blue. Use caution and be sure to follow the manufacturer’s instructions.

Freshwater bath – place infected fish in the freshwater bath for a period of three minutes or until the fish shows signs of stress.

Low salinity (hypo salinity) treatment – lower the salinity in the quarantine tank to a specific gravity of 1.011 and maintain at this salinity for 21 days. Do not use this treatment with invertebrates or especially sensitive fish such as sharks and rays.

Nitrofurazone – an antibiotic that has some antiparasitic action, and can be helpful when used along with formalin dips.


Fungal Diseases

Fungus (Saprolegnia)
Symptoms: Tufts of dirty, cotton-like growth on the skin, can cover large areas of the fish, fish eggs turn white.

Fungal attacks always follow some other health problem like parasitic attack, injury, or bacterial infection. The symptoms are a gray or whitish growth in and on the skin and/or fins of the fish. Eventually, if left untreated, these growths will become cottony looking. The fungus, if left untreated, will eventually eat away on the fish until it finally dies.
After ascertaining the initial cause of the fungus and remedying that, use a solution of phenoxethol at 1% in distilled water. Add 10 ml of this solution per liter of aquarium water. Repeat after a few days if needed, but only once more as three treatments could be dangerous to aquarium inhabitants. If the symptoms are severe the fish can be removed from the aquarium and swabbed with a cloth that has been treated with small amounts of povidone iodine or mercurochrome.

For attacks on fish eggs, most breeders will use a solution of methylene blue adding 3 to 5 mg/l as a preventative measure after the eggs are laid.


Symptoms: Sluggishness, loss of balance, hollow belly, external cysts and sores.

Ichthyosporidium is a fungus, but it manifests itself internally. It primarily attacks the liver and kidneys, but it spreads everywhere else. The symptoms vary. The fish may become sluggish, lose balance, show hollow bellies, and eventually show external cysts or sores. By then it is usually too late for the fish.

Treatment is difficult. Phenoxethol added to food as a 1% solution may be effective. Chloromycetin added to the food has also been effective. But both of these treatments, if not watched with caution, could pose a risk to your fish. It is best, if diagnosed soon enough, to destroy the affected fish before the disease can spread.



Head and Lateral Line Erosion Disease – Hole-in-the-Head Disease (HLLD or HLLE)
Symptoms: Begins as small pits on the head and face, usually just above the eye. If untreated, these turn into large cavities and then the disease progresses along the lateral line.

Head and Lateral Line Disease is also known as Hole-in-the-Head Disease, Lateral Line Erosion (LLE), and Lateral Line Disease (LLD). In saltwater fish it is occasionally referred to as Marine Head and Lateral Line Erosion (MHLLE) or Head and Lateral Line Erosion Syndrome (HLLES).

Though its cause is not definitively determined, a recent study was conducted by Jay Hemdal and reported in Coral Magazine in the spring of 2011. The focus of the study was to evaluate the relationship between the use of activated carbon in aquariums and the development of HLLES in surgeonfish. From the results of the study, it has been suggested that HLLE is a result of activated carbon used in the aquarium. Fish from the study that developed HLLE were in two control groups, one group treated with unwashed lignin carbon and the other with pelletized carbon. A third group of fishes were in a control group where no carbon was used, and they did not develop Head and Lateral Line Disease.

The study was conducted only on marine fishes. Not all species of fish show the same symptoms of the disease however, and they do not always develop lesions to the same degree. It has been suggested that in freshwater fishes the causes seem to be different, but that is not yet substantiated.

Previously Head and Lateral Line Disease was thought to be caused by a poor diet or lack of variety, a nutritional deficiency of one or more of: Vitamin C, Vitamin D, calcium, and phosphorus; lack of partial water changes; or over filtration with chemical media such as activated carbon.

The best treatment suggestions at this time are to use a quarantine tank that offers a stress free environment with good quality water. Provide a quality diet including vegetable foods, places to hide, and a quiet area for the aquarium.

HLLE has been reversed by one or more of the following treatments:

Remove activated carbon filtration

Increase frequent water changes.

Add vitamins to frozen foods.

Add the addition of flake foods, as they are enriched with vitamins.

Add greens, either frozen or in leaf form, to the diet.

Decrease the amount of beef heart as it lacks many critical nutrients.

(This disease is often confused with another disease called ‘Hexamita‘, because both these diseases are often seen simultaneously in the same fish. Hexamita is a protozoan disease that attacks the lower intestine. Discus and other large cichlids, especially Oscars, are especially prone to Hexamita.)


Eye Problems
Symptoms: Cloudy cornea, opaque lens, pop eye, swelling, blindness.

Cloudy cornea can result from a bacterial invasion. Antibiotics may help.

Opaqueness can result from poor nutrition or a metacercaria invasion (grubs). Try foods with added vitamins and changing the diet to include variety.

Pop eye (exophtalmia) can result from rough handling, gas embolism, tumors, bacterial infection, or vitamin A deficiency. Gas bubble or bacterial infection can be treated successfully with penicillin or amoxicillin.

Blindness can be caused by poor nutrition or excessive light. Lowering the light level and a change of diet to include lots of variety may help prevent it.


Swim-bladder Disease
Symptoms: Abnormal swimming pattern, difficulty maintaining equilibrium.

Swim bladder problems usually indicate another problem listed here. If you suspect swim-bladder problems in a fish, first check and treat it for other diseases as listed below:

Congenitally deformed bladder

Cancer or tuberculosis in organs adjacent to the swim bladder


Poor nutrition

Chilling or rapid fluctuations in temperature

Serious parasitic infestation

Serious bacterial infestation

If you have eliminated other causes, make sure you are feeding the right food and make sure the fish is not constipated. Give it live food for a while to ensure it is getting enough roughage. Also, check the temperature for your fish’s requirements and keep the temperature stable.


Non-infectious Maladies

Physical Injuries
Even in the best of aquariums under the supervision of the most astute aquarists, injuries occur. Sometimes a bully fish is the culprit, or sharp decor. Sometimes there appears to be no explanation. As in the human world, accidents happen. If the cause of the injury is obvious, it should be remedied. Then the injury should be treated. The injury should be touched with 2% Mercurochrome, which is supplied commercially. Also, depending on the fish’s tolerance to water conditions, keeping the fish in slightly acid water should speed recovery (pH 6.6). Minor injuries, if the water conditions are good, should just heal themselves.


Some fish are more susceptible to constipation than others. Usually fish with more compressed bodies like angelfish and silver dollars. Symptoms are loss of appetite and swelling of the body. The cause is almost always diet. Usually, with a change of diet, the condition rights itself. But in stubborn cases try dried food that has been soaked in medicinal paraffin oil. Glycerol or castor oil may also be used. If the diet is changed on a regular basis and live foods offered occasionally this condition may never occur.


Tumors can be caused by a virus or a cancer, but most tumors are genetic. The genetic tumors may be caused from too much hybridization, common amongst professional breeders. Practically all tumors are untreatable. If the fish is in distress, it should be destroyed.


Congenital Abnormalities
Abnormalities usually occur when professional breeders are trying to acquire certain strains in breeds. Most are beneficial abnormalities like albinism or extra finnage. But undesirable abnormalities crop up and are usually culled out by the breeder. However, such abnormalities sometimes happen in the amateur aquarium.
If the abnormality is not life threatening or degrades the quality of life, just leave it be and brag to your friends about the unusual inhabitant. Otherwise, the fish should be humanely destroyed.


Viral Diseases

Symptoms: Nodular white swellings (cauliflower) on fins or body.
Lymphocystis is a virus, and being a virus, it affects the cells of the fish. It usually manifests itself as abnormally large white lumps (cauliflower) on the fins or other parts of the body. It can be infectious, but is usually not fatal. Unfortunately, there is no cure, but fortunately this is a rare disease. There are two suggested treatments. One treatment is to remove and destroy the infected fish as soon as possible. The other treatment is to simply separate the infected fish for several months and hope for remission, which usually does occur.