Fin Rot in Fish: Causes, Symptoms, and Treatment

fin rot in fish

Fin rot is a widespread disease found in the fishes and is an easily curable and preventable disease. These diseases start around the edges of the fins and then move on to spread to other body parts of the fish. If left untreated, the disease can even get inside the fish’s body, mixing up with its blood. Also, it sometimes paralyzes the body of the fish so it can not move from its place.

Fin rot is usually caused by a bacteria called Pseudomonas fluorescens. In some cases, it is also termed as a fungal disease. To develop a better understanding of how to cure fin rot, one needs to have a basic knowledge of the symptoms of the disease.

To know more about different Saltwater and Freshwater Aquarium Fish Diseases, click this article “Aquarium Fish Diseases: Causes, Symptoms, and Treatments“.

Symptoms of fin rot disease

If not treated on time, fin rot can cause serious illness. Thus, it is crucial to learn the primary traits of the disease.

The fins shape changes. The fins generally get deformed as a cause of the disease. First, the fin is damaged at a smaller scale, and then with time, the damage can be seen over the entire fin tissue. It even causes the fins to shed away.

Fin rot also develops a hole in the fin of the infected fish. Further, the fin becomes colorless. White dots and red streaks can be seen on the entire fin, and the edges of the fins tend to turn black or brown due to the inflammation. Also, the fins swell up and generate ulcers, when affected severely. The fish becomes listless.

We now get a better understanding of fin rot in the fish and can figure out how to treat fin rot effectively. Now, the fundamental causes responsible for fin rot are equally important.

Causes of fin rot

The grounds of fin rot are:

  • Firstly, the fin rot disease is caused by bacteria, such as Pseudomonas, Aeromonas, and Flexibacter. Although these bacteria are not that harmful, at times when left unchecked, they can cause severe diseases.
  • The other principal cause of fin rot can be contaminated water. It can be caused by overfeeding the fishes. Overfeeding leads the fish to excrete more and more, thus, producing ammonia and nitrite into the fish tank. These chemicals are an essential cause of fin rot.

Thus, one can also hold these reasons responsible for the fin rot in the fishes.


  • Fin rot is an easily curable disease. However, significant steps should be taken to treat fin rot and thus, avoid any further fatal consequences.
  • It is essential to clean up the tank of the fish regularly. However, one needs to avoid using any chemical or soap and shampoos for cleaning the tank. Further, the infected fish should be separately detained in another container to prevent infecting other fishes.
  • Also, the water in the fish tank should be changed partially, twice a week. Fill the cleaned up the tank with unchlorinated water and also clean the belongings of the containers. When the filter in the tank is thoroughly cleaned, partially replace the tank’s water.
  • Clean the filters of the tank and the minutest of the dirt in it.
  • Regularly check the pH level of the water tank. The appropriate pH for water is 7-8 pH, and the ammonia and nitrate levels are required to be zero.
  • Thus, after cleaning up the entire tank, now the fish can be put back into the container.

Fin rot medicine

One can use several antibacterial and antifungal medications for treating a fin rot. However, medicinal treatment is advisable to be taken only in case the steps as mentioned above, don’t work.

Various antibacterial medicines can be purchased from Amazon. Now, while buying medicine for the fish, one needs to have a good understanding of the kind of fish. Different types of drugs are available for different fishes such as goldfish, Betta fish and tropical fish. Now, as these medicines comprise of antibiotics which are responsible for killing the fungal infections, proper dosage of the drug is required.

The best medicine for treating fin rot is Tetracycline. Other essential drugs for treating fin rot are Jungle fungal Eliminator, Maracyn, WaterlifeMyxazin, and Melafix. Melafix for fin rot is very beneficial for fin rot treatment.

Tea tree oil is also a treatment of fin rot and other bacterial and fungal fin rot. However, this tea tree oil is mostly used for the prevention of fin rot. For better results, mix the oil with antibacterial medicines.

Another important method for treating fin rot is with salt. One should use either tonic salt or sodium chloride. However, avoid using iodized table salt for fin rot treatment.

Also, it is crucial to supply the tank with an excess of oxygen as the medicine generally pulls away from the oxygen from the water.

However, one should avoid carrying on medicinal treatment for a longer time as it can cause severe side effects.

How to prevent fin rot

Now, to avoid fin rot diseases, one can take the following steps:

  • Clean the tank regularly to avoid any unwanted substance.
  • Change the water in the tank partially every week since contaminated water gives way to fungal fin rot.
  • One can add some marine salt in the water tank to ensure a disease-free environment for the fish. Furthermore, the pH level of the fish tank is required to be kept updated.
  • Overcrowding the fish tank can also result in fin rot disease as due to irritation and stress, the fish might end up biting each other.
  • Also, it is essential to feed the fish with a proper diet. Inadequate and low-quality food can result in the occurrence of fin rot disease. Thus, one must try feeding the fish with appropriate quality food to avoid fin rot in the fishes.
  • One must also try to avoid overfeeding the fish as the fish then starts excreting more, giving rise to an increase in the decomposed matter. This decomposed matter then produces ammonia and nitrite which are majorly responsible for the initials of fin rot in the fishes.
  • Any leftover food should be removed from the fish tank so that it doesn’t give rise to the disease of fin rot.


Therefore, it is crucial to have an understanding of how to get rid of fin rot disease. Through this article, we also have come to the basic idea of how to treat the fin rot disease and the various basic methods of treating the same. For a better understanding of the disease and its treatment, we have also discussed the reasons responsible for the occurrence of the disease and even the symptoms of the disease. Furthermore, the necessary medicines mentioned above also go a long way in curing the disease which had already affected the fish in the tank. One can now tell how to treat fin rot.

To know more about different Saltwater and Freshwater Aquarium Fish Diseases, click this article “Aquarium Fish Diseases: Causes, Symptoms, and Treatments“.