Hey I got a purple tang next day my achilles arrived and i mixed the rocks around a little and all seemed well. The purple tang had no white spots on him and the people i got him from had him qt for a while same with achilies so I was hoping it was just the achilles was messing with him although now they do not bother each other. My coral banded shrimp also actually got ahold of my purple and got a few pinches in on him but I did not see any marks Tank is 135 gallon and achilles has no marks with him. Just wondering if it is a disease or hopefully just marks from the other tang entering the tank. He has not eating the mysis shrimp but both tangs are picking at the rocks eating stuff... Other side has same white mark with one on his face. I put the net in and he did not even swim away from it he just sat there next to it and did not even swim away to fast if I was to net him. In the dark he has black thick mark down his side.