I’ve had this Tang for about 18 mo thd.It was pulled from my 240g due to an Ich outbreak when I introduced the juvenile Emp you see photobomb the video. They both went through four weeks of Cupramine in QT and were put into a new tank (new water, same rock and pvc as in QT) about three weeks ago. It ate and did fine through treatment, did fine the last 17 days in the new tank and then suddenly started acting strange a couple days ago. You can see something going on with it’s body in the pictures...It’s not Ich, pretty sure not Velvet. The Emperor looks fine, eats, etc. any ideas?