Types of Fish Diseases, Prevention & Treatment

Aquarium fishes are exposed to several types of diseases. Most of the diseases are very common and easily treatable. By knowing how diseases in Fish occur, you will be able to better prevent them or treat them.

Preventive measures

  • There are several micro organisms which can cause an infection, but these organisms just simply can’t mess with fishes. It’s because Fishes have the natural immunity to fight off with microbes but if the fish has got an open injury on its body by chance, fighting for an instance, There lies an higher chance for fungal attack, In such cases it is advisable to keep the affected fish in a separate tank in order to treat and prevent further infection or disease spread to other fishes in the tank.
  • While introducing a new fish into the tank, It is not advisable to empty the fish directly into the tank. It’s because Harmful microbes may be present in the water in which the fish are transported from the store.
  • Stress can also play a major role in disease occurrence. It is important to keep a close watch on the behavior of the fishes. In most cases, a fish that is bullied repeatedly are highly stressed are found with scale damage because of the repeated attack by fellow fishes and that may pave way for fungal infection. In such cases it is advisable to keep the affected fish in a separate tank until it get cured. Friendly fishes may be added to the tank gradually to improve the mental health of the stressed fish.

Types of Fish diseases

Fishes Diseases are majorly caused by three types of micro organisms. They are bacteria, fungi and viruses
Let’s look into the various types of fish diseases that are caused by these micro organisms

Fish Diseases caused by Fungus

Some of the common Fish Diseases caused by fungus are,
1. White spot
2. Velvet disease
3. Flukes
4. Hole in the head
5. Saprolegnia fungus
Let’s know more about these diseases and treatment procedures to cure Fish Fungus.

White spot

Tiny white spots appear over the fish’s body. These ulcerate, releasing more microscopic, free – swimming, infective tomites to attack other susceptible fish.
Treatment : Treat the fish using store bought fungal medications

Velvet disease

Most often occurs in anabantoids. The disease causes the fish’s body color to become yellowish – gray. The fish will rub itself to relieve irritation, and it may display signs of breathing difficulty.
Treatment : Can be treated with store bought medications.


These can attach to the skin or less conspicously in the gills, resulting in labored gill movements.
Treatment : Store bought medications should help.

Hole in the head

This is most likely to occur in discus fish, but it can also strike other fish. It is usually starts with a white spot in the head and further develops to the serious extent of creating a hole in the head.
Treatment : Anti fungal medications such as miconazole can be the best possible treatment

Saprolegnia fungus

This fungus usually strikes after an injury, causing a white haloed effect over the affected area. Ineffective spores are in the water
Treatment: Can be treated with topical creams and liquid baths.

Fish diseases caused by the Bacteria

Some of the common fish diseases caused by bacteria are
1. Fin Rot
2. Vibriosis
3. Piscine tuberculosis
Let’s know more about theses diseases and how to treat them.

Fin Rot

This often strikes following damage to the fins and results in reddening of the damaged areas. The risk is greatest if the water is poor.
Treatment : Can be treated with store bought medications


There are several serious, generalized signs of infections, including reddening of the body, changes in colr and swollen abdomen and eyes and it very serious and spreads through out aquarium.
Treatment : Treatment with Antibiotics is Required.

Piscine tuberculosis

There is a chronic loss of weight and colour, and the eyes may protrude abnormally. There will be widespread losses in the aquarium.
Treatment : Generally No treatment is possible. Isolate the fish from the tank and disinfect it

Fish diseases caused by viruses

Some of the fish diseases caused by viruses are
1. Lymphocystis
2. Malawi Bloat
3. Iridiovirus
Let’s know more about these diseases and its treatment possiblities


Most likely to be seen in goldfish, but it can strike other fish too, isolated white nodules will form on the body surface. It is disfiguring but causes the fish little discomfort
Treatment : Treatment is not very much possible.

Malawi bloat

A problem that affects cichlids from Lake Malawi, especially vegetarian species. The abdomen becomes abnormally swollen and the eyes may protrude, a condition referred to as exophthalmia.
Treatment : No direct treatment is possible. A diet that rich in fibre may help .


Body colour of the affected fish darkens noticeably, with the abdomen swelling. It affects many fish
Treatment : No Treatment is possible