I'm sorry mate, but I do not know the treatment for swim bladder disease...I do agree with Brian (jeep) that the way the fish swims looks like swim bladder but the location of the swelling is more like intestinal blockage. Do you feed freeze dried food? If it is not fully saturated when ingested it can soak in fishes gut juices and get "stuck" causing a blockage, hence the Epsom salt bath.