Cobolt

Hi All, I have what appears to be a sick Blue Gourami. I've had him for a couple of months but in the last week he's been acting odd, seems to prefer to "stand" on his tail literally. I've watched him swim up quite stongly only to float down again. He hasn't been eating either. I put him into a breeder tank to give him a chance of feeding on his own but that didn't help. When I tried to catch him he didn't seem to have much trouble trying to swim away. I also have Female Blue Gourami which appears to be fine as do the rest of the comunity. Any suggestions?