angels, triggers, and tangs are all hit or miss in my experience. ive had a vlamingi tang go nuts on my lps and xenias, and had an angel do the same. both were sold to me as reef safe before i knew any better. sometimes you just gotta see. ive also seen a full mixed reef stocked with all kinds of angels, triggers, and lionfish. the key to that tank was heavy feeding and filtration. the fish were always full so they never got hungry and curious about the corals. he had a humu humu and a clown trigger, both are supposedly reef destroyers