Not sure where you got him from but that is unbelievable! I can't believe someone would do that to a tang, and no it won't grow back. As far as removing for ease of handling, it's a fish that swims in a tank of water why would someone be handling it. Unless wherever the fish was originally distributed by had far too many tangs in far too small of tanks to make it to where they couldn't kill eachother, but either way this is by no means what should ever be done and wherever you bought the fish from I wouldn't buy from again