Aquarium Fish Diseases

Constipation fish
Non-infectious Diseases

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.
Physical Fish Injuries
Non-infectious Diseases

Even in the best of aquariums under the supervision of the most astute aquarists, injuries occur. Some times 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.

Congenital Abnormalities
Non-infectious Diseases

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.

Tumors
Non-infectious Diseases

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.

Lymphocystis
Viral Diseases

Symptoms: Nodular white swellings (cauliflower) on fins or body.

Lymphocystis is a virus and, being a virus, 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. 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.

Bacterial Diseases

Tail Rot & Fin Rot
Bacterial Diseases

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.

Scale Protrusion
Bacterial Diseases

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.

Dropsy
Bacterial Diseases

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.

Tuberculosis
Bacterial Diseases

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 over crowding 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 over crowding 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.

Mouth Fungus
Bacterial Diseases

Symptoms: White cottony patches around the mouth.

Mouth Fungus is so called because it looks like a fungus attack of the mouth. It is actually caused from the bacterium Chondrococcus columnaris. It shows up first as a gray or white line around the lips and later as short tufts sprouting from the mouth like fungus. The toxins produced and the inability to eat will be fatal unless treated at an early stage.
Penicillin at 10,000 units per liter is a very effective treatment. Treat with a second dose in two days. Or use chloromycetin, 10 to 20 mg per liter, with a second dose in two days.

Fungal Diseases

Ichthyosporidium
Fungal Diseases

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.

Fungus (Saprolegnia)
Fungal Diseases

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.

Parasitic Diseases

Leeches
Parasitic Diseases

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.

Nematoda
Parasitic Diseases

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.

Flukes
Parasitic Diseases

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.

Ergasilus
Parasitic Diseases

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.

Protozoan Diseases

African Bloat or “Malawi Bloat”
Protozoan Diseases

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.

Chilodonella
Protozoan Diseases

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 80º F.

Glugea and Henneguya
Protozoan Diseases

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.

Neon Tetra Disease
Protozoan Diseases

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. 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.

Marine Ich (Cryptocaryon irritans)
Protozoan Diseases

Symptoms: Salt-like specks on the body/fins. Rubbing or scratching against decor or substrate, Excessive slime. Problems breathing (ich invades the gills), Frayed fins, Loss of appetite, Cloudy eyes, Abnormal swimming.

Marine ich or white spot disease is one of the most common maladies experienced in the marine aquarium, with the other being Marine Velvet. This protozoa has 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, the small white spots similar to a sprinkling of salt 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, they cycle faster in a warmer environment. 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 a timely manner.
So 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.

Chemical treatments for this disease include using copper, formalin, or a combination of copper and formalin. Follow the instructions provided by the manufacturer.
Natural methods include either a quarantine tank with a low salinity (hyposalinity) or large frequent water changes. 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 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. 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. This immunity is short-lived lasting only about six months and may not be a total immunity, being a small amount of infestation rather than extensive infestation.