For the last week or so, my Betta has looked a bit bloated. Then he started swimming poorly (he looks bent) and just sitting around on a leaf all day. So I did a big water change, fed him some pea, didn't feed him for two days, then gave him more pea. He looks less bloated now, but it still a bit bent and swimming not so well. Poor thing looks rather sad sitting around on the plants all day. I don't think it's the water because the other fish are fine (some bronze catfish). What should I do? ???