Thay are not extremely hardy like a coral beauty. They are very shy and cryptic in nature, it took the one that I bought a few months before he would come out to eat when everyone else was being fed.
I would say that they need to go into an established reef tank with plenty of live rock so that they can forage on sponges and stuff from the live rock until they get comfortable with your tank and lighting. Part of it has to do with where they are caught. They are a deep water pygmy so our 1000 watts of lights don't fare well on them.
He is a SPS nipper but not enough to kill the coral. Possibly nipping at the slime but can't say for sure.
I've caught him pecking at my clams every once in a while, but again not enough to damge the clam.
Took him a couple of months but now he eats frozen prepared foods with everyone else.
I feed a combo of marine cusine, emerald entree, plankton, squid, angel/butterfly formula and mysis on a daily basis.
He's in my 120g reef tank.