[Sk8r]

I am used to seeing ich as a discrete bump, not this flaky appearance. I'd suggest going to a fish disease site and giving a thorough lookover.

There is no way to save this fish [or any other fish that takes it] except by qt and proper medication. NEVER treat your main tank by any means whatsoever...it will destroy your rock and sandbed and crash your tank. The things that claim to treat ich in the tank---no: if you're lucky, they simply don't save the fish: if you're not lucky your fish dies and the tank crashes. The only safe in-tank thing to do is feed him crushed garlic and crossing your fingers---in which case he will probably die and any other tang you get in there will probably take it, if it is ich. This will be true for about 8 weeks, supposing the parasite finds no other host, and that clownfish swimming past would be a prime host unless it has already shaken off a case of ich and has some immunity.

Sorry, but there is no shortcut to a cure in this parasitic infestation. It's like fleas. Only generally lethal.