Noticed what I thought was a scratch from swimming around to then more white spots as a couple days went by. Mind you I QTed all fish in copper followed by prazi pro. They have been all healthy and still look healthy to this point. I started adding corral over the last 6 months but I only dip them then place in MD I know...so my immediate reaction yesterday catch all 6 fish and place in QT tank but to find out this morning the purple tang litterlly has no spots anymore! Any idea on possibilities. I haven’t started copper or anything yet.