I have a Hawaiian Blue Spotted. All he does is prowl the rocks, looking for food. IME, any invert is far game. He will sit and hound some of my large snails, picking at whatever he can get, a snout, eyes, antenna, etc. He picked at elongata xenia, and for whatever reason, did a number on my Bali Green Slimer. The rest of the SPS (poccil. monti capps, and acros) and all of my gorgonians, a toadstool, and my BTA's have been safe.
Also, what size tank? I strongly disagree with a lot of people on this one, but my puffer was QT'ed in a 55gal, and he was very unhappy being confined in there. Moved to my 125gal, completely different fish.