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My female betta has a lump and is lethargic. How to treat her?

Updated On September 23rd, 2025

Pet's info: Fish | Betta | Female

Hello. I have a female betta fish; she swims alone in her tank. I recently noticed she has a large lump on her left side. It’s not white, and from what I read online, I think it’s an abscess. She swims slow and stays at the bottom of the tank most of the time. When I feed her, she struggles to swim and eat. Then she’ll swim back to the bottom. Any recommendations on how to treat my fish? Thank you!

1 Answer

Most Helpful Answer

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Answered By Dr. Strydom, DVM

Veterinarian

Published on June 16th, 2020

Without seeing her myself it is hard to say what the lump is. It could be an abscess, an ulcer or a tumor. There are other causes of lumps that may be mistaken for tumors including: fluid retention, swim bladder disease, and constipation. If the lump is white, then yes, it is most likely an abscess. You can try this product but typically it will need to burst on it's own. You need to be very diligent about keeping the water clean. You can refer to the article below: https://www.amazon.com/dp/B06XDFJ5XN?tag=bettasourcesite-20 https://bettasource.com/betta-fish-tumor/

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