Sideways floating betta

missingmoon

Just earlier today I noticed my betta was having trouble staying down and kept floating up. Once I watched him more closely I realized that he kept "listing" from side to side. He can't seem to stay upright unless he's against the wall of the tank. I have a double tank and there is another betta in the other side. They've been together for about three-four months now. I've had the sick betta for a year and a half and I just changed their water the other day. Oh and it might just be my imagination but it seems as though his belly is a little swollen. Any idea what might be wrong with him?

Meatpuppet

good possibility he's bloated and constipated. feed him a defrosted, cut up, pea. the pea should clear out his insides and make him poo.

what is your tank size.
does it have a heater.
what are the water parameters