Sailfin tang I picked up about a week ago, was doing fine at first and now it’s been laying down on the bottom and hiding, only other fish I have is a small clown fish. Got my water tested and everything was perfect. Has not been wanted to eat also picked up the nori pack and hung it on the side it was close to, to see if it would eat, and nothing. Have not notice anything strange, or any long white feces, PLEASE HELP