I've had this guy for about a year now and the previous owner had him for several years. He's a good size, very active and likes to pick on the occasional coral. Probably 5" or so and eats EVERYTHING.
I had him in my reef and he seemed to only pick on things he found tasty. That ranged from SPS to zoas. Not all of them, just some. Never bothered the clams though. I would say reef cautious. He's in the big sump now but he needs more space. I can provide pictures tonight.