Hello, I've just noticed that my new tang has some ich on it. Non of the other fish in the tank seem to have ich. The tang is behaving normally, swimming and picking algae off rocks although not eating nori or frozen foods at the moment. Doing a fallow period is not possible at the moment. Some posts from forums have said that the tang will naturally fight it off as it is behaving normally. Should I leave it as be unless it worsens or take action immediately (and how)?