How long have you had these fish? Is there LR in the tank? It's not uncommon for new fish to refuse food for a few days. Angels get a good deal of nourishment from algae/diatoms that they pick off the rocks and glass. How old is your tank? Most centropyges are good eaters once established. Try things like chopped mussel, sponge based formulas, mysis shrimp, finely minced clam, scallops, etc. You should also have algae sheets available most of the time for them to graze on.