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My Betta fish is lethargic, barely eating, and has raised scales. Why?

Updated On September 23rd, 2025

Pet's info: Fish | Unknown - Fish | Male | unneutered | 10 months and 6 days old

My male Crowntail Betta fish is acting very lethargic, he stays at the bottom of the tank and only coming up for air, barely eats, his stomach looks hollow, and the scales along his back are raised. He has been this way for a few weeks but isn't getting better. I change his water weekly, and he lives in an environment where his is not caused stress.

1 Answer

Most Helpful Answer

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Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on December 4th, 2016

Check the water quality. This can be done with a home test kit or you can submit a water sample for testing. Most pet stores or aquarists will do this for free or for a nominal fee. Correct any imbalances as indicated. Check the water temp as well. Aim for 78 F to 80 F. Use a tank heater to prevent temps below 74 F. Offer a good quality pellet such as Hikari BioGold. You can also feed blackworms or bloodworms. Live worms may get him eating. Freeze dried tubifex worms may also stimulate his appetite. If there are no outward signs of bacterial or fungal infection, consider parasites. You can use metronidazole for fish. It is sold in most pet stores in the aquarium section. Follow label directions and gauge his response after treatment. The raised scales are a concern because that can be a symptom of dropsy. Dropsy is common in bettas and usually fatal. It is typically accompanied by a swollen abdomen though. Fish tuberculosis is another serious concern. This is a slow, progressive illness that can kill fish and ruin tanks/bowls. Start with the basics as listed above. Try water changes with conditioned water and offer different foods to get Thorin eating. You can request a consultation to discuss his condition in greater detail and for additional resources.

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