Fish Fin Rot - Fish Disease

Updated April 21, 2020
Author: Sabi - Fishlore member
Social Media: FishLore on Social Media

Fish Fin rot is a bacterial disease that commonly affects aquarium fish. Fin rot is also a disease that can easily be prevented by maintaining correct care for the fish and at the same time very easily caused by incorrect care, such as, bad water conditions and injury, one way or the other. Fraying or torn fins, enflamed fin base and, if not treated in time, the fin rotting away are symptoms of this disease. White may appear on the affected parts which is generally bacteria. As the disease advances the fins will get notably shorter, becoming red and enflamed along with bloody patches.

Fish Fin Rot

What Causes Fin Rot?

Poor water conditions are the main causes for this disease. The stress from bullying and fins being nipped by other fish resulting in injury are also common reasons for finrot. overcrowding, over feeding, lack of weekly water changes and decaying matter are some other reasons for bad water conditions. Aggressive tank mates, generally, the larger fish and fish that are famous for nipping can result in fighting and nipping, whereas injury is sure to follow. Sharp edged decorations can tear and injure fish and their fins. Fish seem to enjoy water changes but skittish fish dashing against the decorations and sides of the tank can cause injury, so gentle water changes are in order.

How Do I Treat Fin Rot?

Maintaining proper care is vital for a healthy aquarium. Weekly water changes, monitoring the water chemistry with a Master Test Kit (nitrate, nitrite, ammonia, pH) as well as checking for decaying plants, food etc should be done at least once a week. When introducing new fish, be sure to observe that they are settling in nicely and that there is no aggression. Quarantining new fish is recommended for easier observation for disease. Treatment has to be applied before the disease reaches the fish's body as this will lead to death.

When fin rot is detected check that your water conditions are in order. A 50% water change should be made and the rest of the fish should be checked for any signs of the disease. The affected fish should be removed and put into another tank and treated separately. Most medications recommend not doing water changes during treatment so a 50% water change before starting is advised. The temperature should be raised to 80-82'F (26-27'C) and the water kept extra clean. After the treatment another 50% water change must be made to help clear the medicine and thereafter 10-15% every other day for a week while monitoring the fish. According to our knowledge the use of the following medicines will help cure the disease. Maracyn, Waterlife-Myxazin, MelaFix, and for betta's Bettafix. Alternatively the use of Methylene Blue too can be used. 1 Drop per 2 gallons of aquarium water is our choice. While treating with Methylene Blue, a 50% water change every other day for a week is recommended, the main reason being, as mentioned before, clean water is essential and helps with the healing. When using Methylene Blue be sure not spill any as it stains.

Treatment should always be carried out to completion and affected fish observed.

References / More Information

Fishlore Members:
- Chief Water Changer, Tom, Armadillo, Butterfly, Tazmiche
- Wikipedia

About the Author

Sabi is from South Africa and started fish keeping with goldfish five years ago. There after the hobby slowly but surely grew. I've kept Goldfish, Koi, Malawis and now tropical freshwater fish. I currently have two running tanks, a 67 gallon and a 2 gallon. The 67 gallon aquarium is a community tank consisting of Angelfish, Tetras, Rasboras, Plecos, gourami and corys and the in the 2 gallon I may add a betta. I one day hope to breed either Discus or Angelfish.

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