What causes swim bladder problems in a betta?

Feed her some cooked peeled peas. This usually clears up the swim bladder issue. It could take a week or more to clear it up so be patient. Swim bladder issues can be caused by swallowing air accidentally. to prevent this, get a sinking pellet food. A 5 gallon heated and filtered aquarium is considered the minimum for 1 betta. I would suggest a bigger tank. Also if you got her from a store and your tank is heated, you are supposed to stick her bag of water (with her in it) in the tank and let it float around for 20 mins or more. Her cup at the store probably wasnt heated and putting her in a warm tank might have put her in shock. There really isnt anything you can do about this, just try to prevent it in the future. Bettas are warm water fish so they do need a heater. A filter is mandatoryand a 5 gallon tank is the minimum for 1 betta.