This guy has been in QT for 11 days now. He looked absolutely perfect and was eating in the store when I purchased him but he has not eaten since I got him. He is pretty large (probably 7-8 inches) and is currently in my 40 gal qt with a seeded sponge filter and a 110 hang on filter. There are no medications in the tank as I wanted to get him eating first. Other than the white mouth and not eating, he doesn't show any signs of stress, although he is starting to lose color and get skinny. I do a 25 percent water change every two days and water parameters are perfect. Any ideas what is on his mouth and what I should use to treat it? My research has resulted in mixed and inconsistent results. I have tried feeding nori, flakes, and a variety of frozen, pe mysis, fish eggs, etc. with garlic and selcon. Thx.