I've had my darling betta Phycondrias for nearly five months now. When he was in his cup we bought him in from the store, he was docile, but had a full tail. About a month after moving him to his new tank, he started biting his fins. And he hasn't really stopped even though we've been settled in our new place for four months. I've tried keeping the temperature of the room in a comfortable 26-30 degree Celsius zone, though sometimes it gets a bit warmer in the tank. He has a gentle filter, and I don't keep the light on terribly long, since he gets partial natural sunlight all day. So I'm wondering if the tank is too small, or too cluttered. Too colorful? Not enough hidey spaces? The pH is fine, and he's in the same room we're in most often when at home.
This is what his tank looks like, 2.5 gallons..should I move up to 5 so he has more space and I can add more variety?