Showed up yesterday and has gotten a little worse. It's dark around the edges but also has some white inside and around it. It's present on both sides in the same spot. Any ideas here? I dont have a large enough tank to qt it (it was supposedly QTd before arriving) and I can't treat the tank since I have rays in it that don't tolerate same meds. I could maybe try a brute and as an absolute last ditch effort I could maybe setup a very temporary tank to treat it. I run an 80uv sterilizer on a 500g tank. It's one of three fish and the only one affected. It still swims around and eats (about a 5"x5" sheet of nori daily shared with a small bird wrasse)