what size tank do you have ?
your keeping a trigger in a reef tank ? he will in time tear it apart eating all the heads off all your coral, they also grow up to 10+" with a minimum tank size of 180g
Saltwater Aquarium Fish for Marine Aquariums: Humu Picasso Triggerfish
there is only 1 trigger I know of that is reef safe and that's the blue throat and that's with caution the min tank size for these are 125g
Blue Throat Triggerfish
hopefully your tank is big enough to house the tang as they require a tank of at least 125g
it's hard giving sound advice with out your tank specs as you don't have anything listed in your profile
we can only assume