I forget but it's a disease that is almost impossible to treat. I think it's called swim bladder disease. I had that once. Evidently=====WAIT I MEAN I HAD A FISH WITH IT!!!!! OK, now where was I? OK fish with disease. he couldn't stay down, would eat, swam funny of course, but seemed happy and not sick. But eventually I UMM euthanized him by putting him in a plastic bag filled with pond water and put it in the freezer. Figured if I left him in the pond, he'd be easy pickings for the heron and didn't want to encourage big bird.