There's no way I'd buy this fish, but curious as to what could be wrong with it, or if it's just acting weird because it's bored or whatever.
But all it does is swim in a corkscrew pattern over and over, all day. Swimming upside down and everything. The owner's girlfriend says he does it all the time. I think it was a naso tang, not 100% positive.
Oh I wouldn't buy him, he was entirely too big for my tank, assuming he was healthy to begin with. I was just curious as to what could be causing his strange behavior. Maybe he's a psycho fish, but maybe he's got a messed up swim bladder or something, who knows?