Its a little uncommon for tangs to np at coral, they usually only do if they are very underfed and need something to eat. It also may be that they are finding algea around the coral. Fire (i assume u mean flame) angels will eat coral especially non noxious polypy looking ones. This will just depend upon the fish, if u have one that does eat coral u should be very careful the types of coral u put in there. Pulse xenia is a pain in the butt and often just dies keeping a high level of light, iodine, ph
, and giving it a decent water flow helps. The temp. should be steady around anywhere from 76-78. If u have used medication in the qt
tank i wouldnt recomennd putting the coral in there as most meds kill inverts.