Chromie question, Cut or disease?

[SaltLifeBob]

Hello, I have just put 3 Chromies into my 90 Gal tank. I put them in on Monday and have been watching these. They seem to be fine in the tank with my other fish. i have a few tangs and small fish. I have not seen any fighting. Has anyone seen this before? Should I let it ride or pull the fish so it does not infect other fish or water?

Thanks, Bob