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My Betta fish is fat and bloated. What's causing it and how to help?

Updated On September 23rd, 2025

Pet's info: Fish | Unknown - Fish | Male | 1 month and 26 days old

My crowntail beta as said was mail on it's container looks really fat and my other beta gets the same types of food at the same The what's the problem

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1 Answer

Most Helpful Answer

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Answered By Angel Alvarado, LVT

Licensed Veterinary Technician

Published on August 31st, 2017

Your fish is definitely a male Betta. The finnage and vibrant color give it away. His condition has several potential causes ranging from bloated/constipation or swim bladder disease (treatable) to tumor (possibly treatable) to dropsy (usually fatal). It he isn't defecating or has trouble swimming upright, it may be the first two problems, a mass would need to be diagnosed by a veterinarian experienced in treating aquatic pets, dropsy is a serious concern. If your dishes scaled are protruding giving him the appear of a pinecone, he may have dropsy. Dropsy is a severe bacterial infection that affected the kidneys and other organs causing fluid retention and swelling. Many of these conditions are caused by poor water quality or over feeding. Test your water first then correct any imbalances via partial water change using aged or conditioned water. Rinse the filter media and confirm adequate filtration. Check water temperature. Bettas do best between 78 F and 80 F. Cold temps can lead to stress and illness. Fast him for 2-3 days then offer bits of cooked, shelled green peas until he is defecating normally. Switch to a quality pelleted diet afterwards and skip a feeding once a week. If this does not help, he may have a mass or infection. You can use an antibiotic such as kanamycin or Maracyn 2 to treat infection. These you can purchase in the aquarium section of most pet stores. Follow label directions carefully. help with swelling, dissolve a half teaspoon of aquarium salt (NOT table salt) into the tank. Adequate water quality is key to recovery, if filtration is unavailable, daily 25% water changes should be done. Again, use only aged or conditioned water that is temperature matched to prevent further stress or shock. An airstone can be used to increase oxygenation.

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