This article is a guide to help you defeat a fish disease before your fish are harmed from it. there are hundreds of diseases that fish can get, but there are only a few that are really common.

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 fish food. Avoid purchasing fish flake from department stores.
• Avoid stressing the fish with rough handling, sudden changes in conditions, or “bully” tankmates.
• Do not overfeed your fish as food that is left will contaminate the water.
• Disinfect nets used as bacteria will build up on the net from sitting in your cabinet. rinse them under hot water kill the bacteria.
• Do not transfer water from newly purchased fish bags into your aquarium. Net out the fish instead.
• Do not let any metal come in contact with the aquarium water.

About fish all of the fish diseases

Bacteria Infection: 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.

Bacteria Infection: 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.

Bacteria Infection: Mouth Fungus – 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. This bacteria is often accompanied by a second infection of an Aeromonas bacteria.

Bacteria Infection: fish tuberculosis- 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.

Bacteria Infection: Dropsy – 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.

Bacteria Infection: 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.

Bacteria Infection: 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 anguillarum, V. ordalii, V. 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.

Fungal:  Fungus infection – Symptoms: Tufts of dirty, cotton-like growth on the skin, can cover large areas of the fish, fish eggs turn white.

How does it work: 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.

Fungal:  Ichthyosporidium – 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.

Parasitic: Argulus(Fish louse) – 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.
Parasitic: 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.
Parasitic: 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.
Parasitic: Ergasilus – 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.
Parasitic: Flukes – 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.
Parasitic: Nematoda – 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.
Parasitic: Leeches - 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.

Protozoan: Velvet or Rust – Symptoms: Clamped fins, respiratory distress (breathing hard), yellow to light brown “dust” on body.

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.
Protozoan: Costia – Symptoms: Milky cloudiness on skin.

This is a rare protozoan disease that causes a cloudiness of the skin.
Protozoan: Hexamita – 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 it’s head down, 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. As it is a disease of the digestive tract, a wasting away or loss of appetite may be experienced.
Protozoan: Ich – White Spot – Ich, Ick, White Spot Disease – Symptoms: Salt-like specks on the body/fins.  Excessive slime. Problems breathing (ich invades the gills), clamped fins, loss of appetite.

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.

Protozoan: 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.
Protozoan: Chilodonella- 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.
Protozoan: 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.

Non-infectious: Tumors - 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.

Non-infectious: 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.

Non-infectious: Injuries –  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.

Non-infectious: Constipation -   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.

Viral: Lymphocystis – 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.
Miscellaneous: ‘Hole-in-the-head’ Disease – 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). It is attributed to a nutritional deficiency of one or more of: Vitamin C, Vitamin D, calcium, and phosphorus. Though its cause is not definitively determined, it is thought to be caused by a poor diet or lack of variety, lack of partial water changes, or over filtration with chemical media such as activated carbon.
Miscellaneous:Eye Problems – Symptoms: Cloudy cornea, opaque lens, pop eye, swelling, blindness.
Miscellaneous: Swim-bladder Disease - Symptoms: Abnormal swimming pattern, difficulty maintaining equilibrium.

Swim bladder problems usually are an indication that your fish is not getting the nutrition it needs. Its very common with goldfish.

Cures

It is recommended that you turn your heat up to 83F, add aquarium salt, and:

• For ick: a bottle of API Ick cure. This medication contains a dosage of malachite green which is known to be effective to the disease.
• For tail rot: PrimaFix. The medication contains a dosage of pimenta racemosa which is known to assist and heal damaged fish skin.
• For Swim bladder balance issue: The best way to cure this issue is to take off shells of pea’s and feed the inside to your fish. This can be time consuming but does help a lot. Lastly make sure that you are not feeding your fish the wrong brand or type of food. It may be worth it to come to PV Pets and purchase a can of Spirulina which is a very high grade type of fish flake.

Cures – (for all diseases you should put in Aquarium salt unless you already have done so within the past 1 1/2 months) as well as:

Fungal: Fungus & Ichthyosporidium – a bottle of API fungus cure. This medication contains a dosage of acriflavine which is known to be effective to curing fungus infections.

Bacterial   
Red Pest, Mouth Fungus, Tuberculosis, Dropsy, Scale Protrusion, Tail Rot & Fin Rot, Fish Vibriosis – a bottle of API Melafix cure. This medication contains a dosage of melaleuca which is an antibacterial fish remedy to kill bacteria and heal damaged fins, ulcers, and open wounds.

Parasitic 
Anchor Worm – Unknown.
Black Spot – Black Ick – Aquarium salt only.
Ergasilus – a bottle of API Primafix.
Flukes – a bottle of API Ick cure.
Nematoda – Unknown.
Leeches – Aquarium salt only.
Argulus – With larger fish and light infestations, the lice can be picked off with a pair of forceps.

Protozoan
Velvet or Rust – A bottle of api Fungus Cure.
Costia – A bottle of api Fungus Cure and raise the aquarium temp to 83F
Hexamita – Unknown
Ich – White Spot -  A bottle of ick cure.
Glugea and Henneguya – There is no known cure for this disease. It is best to put down the fish.
Chilodonella – A bottle of api Fungus Cure
African Bloat ‘Malawi Bloat’ – A few small dosage of MelaFix Cichlid

Non-infectious     
Tumors – tumors are untreatable – It is best you put down the fish.
Congenital Abnormalities – This is a birth defect from cross-breeding that occurs rarely. If the fish is fine with the defect than do not worry about it, but if the defect makes the fish behavior extremely different, or causes weird changes in the fish you should put the fish down.
Injuries – Injuries can repaired quickly from the assistance of a small dosage of API Melafix,
Constipation – Using live frozen food will really help your fish with this condition.

Viral
Lymphocystis – It is best to put down the fish or quarrentine the fish to its own tank for months and feed it a very high quality food. For cichlids frozen food, for freshwater and cold water, OSI Vivid color or Spirulina.

Miscellaneous
Head and Lateral Line Erosion – Make sure to have a high vegetable content food like OSI Freshwater fake, and mixed it with crushed up adding greens or leaf form veggies from your fridge. Increase your water changing behavior to removing 30% of the water every two weeks. Avoid using water conditioner and just let buckets of water sit for 30hrs before adding them to your tank. Remove any carbon bags(cartridges) from your filter, And use API Sludge destroyer(only two 1/2 of the suggested dosage).
‘Hole-in-the-head’ Disease -
Eye Problems – API Melafix or API pimafix should help this issue that this is most likely a bacteria infection.
Swim-bladder Disease – To cure this desease switch to a much high veggetable content food such as OSI spirulina. daily you should feed your fish by crushing the shell of pea’s and only feeding them everything except for the shell. Curing this disease can be very quick, but if it looks cleared you should keep doing this for an extra week then slowly wean them away from this food.