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My betta has fin rot. How quickly can it kill and how can I treat it?

Updated On September 23rd, 2025

Pet's info: Fish | Unknown - Fish | Male | unneutered | 10 months and 23 days old

My betta fish have fin rot disease. How fast can kill it my betta? How can i treat it? I can't take a better photo because he can't swim , so he doesn't move. I put in his water what vet recomended me to put. Thanks!

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4 Answers

Most Helpful Answer

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Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on January 27th, 2018

Fin rot can kill quickly if left untreated. Clean water plays a critical role in treatment and recovery. Perform daily partial water changes using aged or conditioned water that is temperature matched to prevent further stress or shock. Bettas do best between 78F and 80F. You can continue to use the bottled treatment as directed. Add a bit of plain aquarium salt (NOT table). As well to aid in recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then reassess fin condition.

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on February 23rd, 2018

    Check the strength of the current caused by the filter. Bettas do best in slow moving water. Continue to maintain pristine water quality. Consider adding in some plain aquarium salt (NOT table or Epsom salt) as a general tonic. It will reduce stress, improve gill function, treat minor infection and aid in any recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then reassess fin condition. Perform partial water changes afterwards to decrease salinity. Use only conditioned water that is temperature matched to prevent stress or shock.

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on August 8th, 2017

    Check and maintain adequate water quality. If you have a filter, set the water flow to as low as possible. Bettas do not do well in strong currents, especiallly with fin damage. Maintain proper water temp (78 F to 80 F). You can add in StressCoat to aid in healing at each water change. It will take time and if he was in very poor condition, his fins may never regain their original form and length.

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on August 26th, 2018

    This looks like fin rot. It can be caused by bacterial or fungal infection and compounded by poor water quality and/or strong water currents. Perform a partial water change, no more than 30% total volume, every couple days to maintain water quality. Use only conditioned water that is temperature matched to prevent further stress or shock. Bettas do best between 78 F and 80 F. If possible, turn down filter flow to decrease current as they also prefer slow moving water. Dissolve 1 teaspoon of plain aquarium salt (NOT table salt or Epsom salt) per gallon in a cup of tank water and gently pour it into the tank. Treat for 10 to 14 days then reassess fin condition. Do not use salt for more than 14 days in a row. The salt will act as a general tonic to reduce stress, improve gill function, treat minor infection and aid in recovery. If necessary, you can use a broad spectrum antibiotic. Find one in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.

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