Emporer/emporater angels have been known to eat coral. If you like coral and your tank has been up for less than a year, be cautious. A young tank will not have the growth of foods that the angel can pick on between feedings.
Have you seen adults for sale? Usually the juvenile is only available. They can get very large. A large tank is needed because trying to limit their growth by limiting their feeding will be murder on the coral. This is the non-dwarf angel most often seen in reefs and I have a picture of one in a members tank living alongside what I once heard was it's favorite food coral, a bubble coral. His is a really old tank. If you want to see it, email me for the image.
Mark [email protected]