How long did you have the fish? Tangs require huge amounts of food, and all are voracious eaters. Mata tangs are unlike many of their relatives in that they require a lot of meat in their diet. If they are being improperly fed their condition will deteriorate very quickly. Are you sure he had something stuck on his spine or was it just sticking out? Sometimes when tangs are in extreme distress their scalpels will stick out rather than laying flat against the body, much like the way they say a dying cat won't have its claws retracted.
