IMHO, "Bobbing" is a sign of air in the swim bladder. You see that at times in wild caught frontosa that weren't decompressed properly. I have also seen it in fish that are stressed. However, laying on his side at the bottom of the tank has never been part of the equation, so you might have more than one thing going on. IMO, Epsom salts is the treatment of choice for 'bobbers' and has always worked well. However, it sounds like you're pretty far into the struggle, so it may be difficult. good luck.
