my new small purple tang got ich already.

If you only go with garlic there is a good chance you will lose the fish. Like other have said this will help, and I would recommend it, but it won't solve your ich problem. In that small of tank with that many fish, the ich will thrive and kill one if not both the tangs.

As far as killing the source , I think you mean killing the source of ich, but correct me if I am wrong, is one of three ways. Copper, hypo-salinity or remove all of the fish for a considerable length of time (8 weeks or more).

Edit: Sorry I missed the point about moving tanks. This might be a perfect time to get rid of ich once and for all. If you keep the fish in one tank and treat it with hypo, and keep the corals in the other for over 8 weeks you will have gotten rid of the ich. I don't know if this is feasible for you but it would work.

 

This is the best way, get rid of the problem once and for all, just remember saltwater ich parasites are commonly found in nature, and we can safely assume that many normal, healthy fish are carrying a few of these parasites when collected. Since no treatment has been found that can kill ich while embedded in the fish, we must wait for all of the parasites to fall off on their own before we can consider the fish to be ich-free. Just make sure you don't go to fast with it and if you decide to use copper make sure you monitor your ammonia levels to.

 

Along with garlic selcon or similar product will help.and some marine c(vitamin c) will also help ...neither of thesd are cure but I've personally had my bouts with ich and with the aid of those plus garlic I haven't lost a fish to ich

 

ok thanks guys, so let me see if this will work... ur saying to take all my coral and rock to the new 125, no fish. take the fish and leave them by themselves for 8 weeks and treat with hypo? can anyone explaine the hypo part.. and then after all that i can re introduce the fish to that 125 and should be ich free. and all the fish right? not just the tangs?