Diseases Diseases

What Is Tailfin Rot?

About tailfin rot

Tailfin rot is a fatal fish disease that attacks fish living in all types of habitats. Tailfin rot is a very common and easy to recognize fish disease. It is a symptom of a bacterial infection. Tailfin rot destroys the tail of a fish before progressing to eat up the whole body and causing death of the affected fish. Tailfin rot causes the fish to be prone to fungal infections that lead to severe complications making it difficult to treat tailfin rot. It is therefore important to observe the fish often so that you can notice changes early and the treatment can begin early enough before other complications attack the fish.

Causes of tailfin rot

Tailfin rot is caused by bacteria that are found in water bodies like ponds and aquariums. The fish becomes prone to this bacterial infection when it an external environment that predisposes it to infections. The most common factors that predispose the fish to infections are; poor water quality that has high levels of nitrite and ammonia and tailfin trauma that could be as a result of bad handling or being hit by sharp objects in the water. There are three bacteria that cause tailfin rot. They are as follows;
Flexibacter: it only attacks the fish and can be seen as bright yellow strains when its grown.
Aeromonas: its rod shaped and attacks humans too.
Pseudomonas: its rod shaped and attacks humans to cause necrotizing inflammation.

How tailfin rot develops in a fish

Once one of the above mentioned bacteria enters the body of a fish, if assembles in the intestines of the fish.  While in the intestine, they generate a mucous that includes molecules that are toxic to the body of the fish. These toxic molecules are enter the bloodstream through absorption. They are absorbed via the intestinal walls together with the nutrients. After the molecules are absorbed in to the bloodstream, the first symptom of tailfin rot which is red streaks in the fins appears. The red streaks are as a result of the bleeding from the broken small blood vessels in the fin due to the action of the toxic molecules. Due to lack of enough blood supply, the fins lose color and begin to rot away. Other symptoms of tailfin rot are;

  • Change in the levels of calcium and haemoglobin in the blood of the affected fish.
  • The edge of the fin appears lighter and smoother.
  • In some cases the edge of the fin appears white.

Treatment of tailfin rot

There are two ways of treating tailfin rot. They include;
Treating the main fish tank/habitat.

  • test the water in the tank
  • change the water in the tank
  • removing all rotting plants or food materials from the fish tank
  • treat the water and the main fish tank

Treating the affected fish

  • give the fish a balanced and nutritious diet
  • put salt in the fish tank as it has natural wound healing properties
  • use antibiotics like chloramphenicol, tetracycline and oxytetracycline.


  • Tailfin treatment should be continued until the fin starts to regrow
  • If the treatment is not working change and use something stronger.
  • Ensure that the water quality and quantity match with amount of medicine used.
  • Avoid having too many fish in one tank.
  • Ensure that the fish are comfortable and stress free.


By winnie mwihaki, published at 03/19/2012
   Rating: 4/5 (11 votes)
What Is Tailfin Rot?. 4 of 5 based on 11 votes.