I have a new Red Margined Fairy Wrasse..lovely fish. Looks like a fully grown male at least 4-5". When I got him a week ago the LFS dismissed the tailfin damage and said it will grow back. It seems to have got a little worse in a week. All other fins are fine.I do have a larger blue tang, but watching the tank behaviour I would guess the male wrasse is probably the dominant fish in the tank even though the Tang is probably a little bigger. I dont see any bullying and I am reluctant to jump into assuming finrot and throwing antibiotics in there. If anything it may have got a little worse rather than better over the week. The fish is otherwise super healthy looking, vigorous and is first to anything that looks like food. Currently eating mixed pellets/flakes, nori pieces and frozen mysis shrimp.Bad photos I know... best I could do.