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Why is my betta fish losing tail and turning gray after fin rot treatment?

Updated On September 23rd, 2025

Pet's info: Fish | Betta | Female

My betta fish is losing parts of her back tail, and I really need help. I've had her for about a year, and she has started to turn gray on her belly. I have already treated the tank for fin rot, but nothing happened. Is it a bacterial infection?

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1 Answer

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Answered By Todd Cecil

Veterinarian

Published on September 15th, 2019

Thanks for reaching out about M.S. and including photos. Have you tested the water quality for pH, ammonia, nitrites and nitrates? Betta pellets need to be replaced every 3 months as vitamins degrade quickly. Bacterial fin infections are often associated with poor water quality. Rarely do water additive for infection improve the condition so systemic antibiotics might be a better choice. A veterinary visit would be needed to diagnose and prescribe medication. good luck.

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