FWIW I have a pygmy angel (Centropyge argi) in my 30g reef and he doesn't bother any of the corals, but I think each fish is different. Try and look for one at the LFS
that is in a tank with corals or at least some LR
and watch the fish to see how it behaves. I didn't get mine until the tank had plenty of other things growing on the LR
for him to snack on; he took one swipe at my big feather duster but when the duster zipped back into his tube it scared the angel so much he hasn't messed with the duster since!