This isn't swim bladder but something else..... Does it sound like this
•Symptoms: It’s hard to say for sure. But maybe your betta is lethargic, not eating, hiding, staying in a corner or at the bottom of the tank, he might look a bit pale or dart away when you get close to the tank. It could be a mild infection of some sort though too so be careful.
Treatment/Prevention: If your betta is housed with other fish then isolate him and see if he get better. His tank mates might be harassing him. On the other hand, some bettas become depressed when isolated. Other causes could be too much or too little light, too much current, too much activity near the tank, the temperature might be too low. Try changing things up, move the aquarium to a more isolated area and see if he gets better. Or if he’s on a food strike, offer live foods. If he is lonely, place the tank where he can see other fish. Make sure there are places to hide when he is stressed.