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My old fish has a swollen belly and swims upside down. What's wrong?

Updated On September 23rd, 2025

Pet's info: Fish | Gold Fish | Female | 17 years and 2 months old

Hi iv had my fish for 17 years and over the past few weeks the belly has become swollen and now seems she only swims upside down unless its feeding time. Its more so on the right side so finds it hard to keep floating as normal..i really dont wanna lose her as been in family so long but im guessing its not a good sign any advice would be great thank you

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2 Answers

Most Helpful Answer

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Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on January 2nd, 2020

This could be swim bladder disease. It can be caused by infection or constipation You can try fasting Stella for 3 days. Resume feeding bits of cooked and shelled green peas until swimming and defecation are normal. Maintain pristine water quality via filtration and regular partial water changes. Use only conditioned water that is temperature matched to prevent stress or shock. Goldfish are cold water fish and do best between 65 F and 72 F. If fasting and green peas do not work, you can find a broad spectrum antibiotic in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated. A broad spectrum dewormer can be used concurrently, if necessary, in case the condition is due to parasites.

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on August 2nd, 2017

    If he has tank mates, separate him out into a hospital or quarantine tank. Confirm proper water quality ( 0 ppm ammonia and nitrites, 40ppm or less nitrates). Fast him for 2-3 days then feed very small bits of cooked and shelled green peas. Feed until he is defecating normally then transition slowly to a quality diet. Avoid flakes as this can cause air ingestion during feeding which can predispose him to swim bladder or bloat issues. Pellets or other foods that sink are best. A broad spectrum antibiotic can be used in conjunction if the peas do not work. You can purchase one (amoxicillin, kanamycin, or erythromycin) in the aquarium section of most pet stores. Follow label directions carefully. Plain aquarium salt (NOT table salt) can be used as well as previously stated. Dissolve 1 teaspoon per gallon of water and treat for 10-14 days. Perform a partial water change afterwards using aged/conditioned water that is temperature and pH matched to tank water to prevent shock.

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