File fish has a bald patch on his back. Eats normally. A clown has a small brown spot on it's side. Also behaves normally. Neither seem to be getting worse. I'm wondering if it's an injury or a disease. We did do some maintenance moving around live rock the day before we noticed it. Thoughts? No new fish. I'm doing a water change but I may have been a little overdue - normally I do it once a month and I waited an extra two weeks this time. I don't have water parameters at the moment aside from salinity- 1.025. Thanks for any help for how to fix...