I got this tang on Saturday and I'm sure I would have noticed this mark on him, at the store soi think it's happened since being in the tank (I noticed it Sunday morning). It runs from his temple to his tail, but doesn't seem to bother him. The only thing I can think of that could have done it is my jardinei coral, but he continues swimming around it and close to it without seeming bothered. Is it just a sting mark or something else? Will it heal or get worse and is here anything I can do?
Sorry this is the best photo I could get