this is probably a question you should have asked before your purchase
sometimes flames will nip at some soft corals and clam mantles, so if you are planning on having a reef it is something to be aware of. many people have had flames in their reef with no problem though. i have a coral beauty in mine that doesn't bother anything.
try giving the flame some seaweed selects or nori as part of its feeding.
great choice on the flame angel! it is one beautiful fish!!