damsel, are hearty fish, but most of us don't like them, because they are highly aggressive(so aggressive that they will even act so towards tankmates much larger than them),
but clowns, firefish(a type of goby) and other gobies, blennies(scooters and lawnmowers),
chromis(which are actually a damsel, but much more peaceful), and i hate to sound like a broken record, but i would not add a tang to a tank under 75 galons(or 4 ft long),
and i too would wait several months before adding corals
HTH