Epsom salt will help with the fish. What are the other tank mates ? Could it be a swimbladder injury ? Sometimes larger fish will bash the other fish when the lights are off and cause the swim bladder to go quits. I have seen this first hand. I would also post in disease/health issues thread and tom maybe can help you he is quit helpful when it comes to this kind of thing. GOod luck and I hope your fish pulls through
He is by far the largest fish in the tank (14") & his tank mates are severums, geos etc so i doubt he has been bashed, he is normaly the one doing the bashing.
can a mod move this to disease/health threads please?