I don't have a saltwater tank, so I can't really help you.
But the SW
experts will probably want more information to answer your questions.
Such as: How old is the tank? How long has it been cycled? When did you add your other fish? What are your water parameters? ammonia, nitrite, nitrate etc.
And maybe more about your setup. Filtering, protein skimmer, powerheads, etc.
And some pics would be cool! I like pictures. (I'm planning my saltwater tank... but have to get my 125 gallon fw