Not a secret shopper thread, BoomerD. We'll look into different ways of rewarding the members for their helpfulness. It was all supposed to be in good fun.
Luistwentyone, BoomerD's info is correct and his advice good. The vast majority of tanks here are reefs, so it's understandable that he would assume you had just put copper into a reef tank- a situation that would be worthy of a good freak-out.
Anyway, sounds like the fish have ich, and the copper should treat it well. But I would not use anything in the tank for a system that will house invertebrates in the future. Since you have a FO, this shouldn't be a problem and in such a tank copper is the most effective treatment I know of. So you did the right thing, you just need to know about the side effects of copper.
Now, some info on the system and water parameters would still be helpful, fish usually get ich for one of two reasons: An infected fish was introduced to the tank, or stress. If you recently added a new fish, the way to avoid future problems is by using a quarantine tank. If not, we should try to figure out what may have stressed the fish.
Travis