Ok, one problem you are having here is that you keep posting the same issue in different threads and no one really wants to follow the trail of this issue all over the forum. I know you're distressed, but opening up numerous threads is not helping you, in fact it is confusing and frustrating.
In filtering through your posts, my understanding is that you have a tang in quarantine and have been treating it with copper. In your main tank you have other fish and inverts. You are not experienced and are insecure about trying some of the other treatment options that Terry suggested, and, in fact, you’re not even sure that your tang has/had ick.
Since you started with the copper treatment, then you might as well continue it. Keep the tang in quarantine for 1 month. Get yourself a copper test kit to make sure that you maintain adequate levels [not too much and not too little] of the copper in your tank for 3 wks or as directed by the brand med you are using. Do weekly water changes. Make sure that you are not running any sort of carbon filtration as this will remove the copper. After water changes, bring the copper levels back up to therapeutic levels. After the 3 wks, if you fish is ok, then, if you can, add carbon filtration to remove the copper. Do a partial water change every few days and don’t add any more copper. Once your fish has been ick – free, then you can return him to his tank—approx 1 mo. During this course of treatment, feed him some food soaked in garlic, and do the same thing for your fish in the main tank.
There is a risk, if this is ick, that your other fish could get ick because they have been exposed. Thus, don’t be surprised if this happens, and you have to treat your other fish too. However, perhaps you’ll luck out and this won’t happen. Feeding the other fish garlic also will give you a better edge.
Good luck, and keep us posted ! [But only on 1 thread, plez]
