Zoo's are like drugs to angels, Brains and similar corals are tasty. Most other corals are okay. Of my three flame angels, two where safe with anything but my female grazes on SPS, but does not kill. I had a juvenile blue face that destroyed everything, and yet had a large male that ate nothing. I had a juvenile emperator that grew up with a clam, and then after several years and becoming an adult it started picking. Did not kill it, I just got tired of seeing the clam shut when the imp got close. Of the most safe so far has been the Regal from the Red Sea, the worse is a Queen. My Copperband is safe except for feather dusters. In this hobby there are no guarantees, I remember selling a purple tang to someone and it ate $200 worth of coral before the fish store could remove it.