Ive had a two bar, a Java, two fox faces and a bicolor.
None picked at corals.
I have seen dwarf angels go after zoas and shrimp go after nems.
Rabbit fish eat buble algae as does my achilles.
A good recipe for eliminating pests like certain algae, bubble and aptisia is a healthy mix of tangs, rabbits, shrimp and a copperband.
If you have bugs get a bluethroat trigger....but then you wont have your shrimp after that....