ladyhart,
I am by no means or measure an expert on disease, so as always I will default to the experts. However, it is my understanding that a freshwater dip will *not* help the situation, only serve to stress the fish even more. Also the copper based medications weren't a great idea, especially if you have any intention of ever adding inverts or corals. They cannot tolerate the copper, and it will most likely seep into the crush coral, or whatever substrate/rock you may have in the tank. From what I have read on these boards, the most effective treatment and the most recommended is hyposalinity in a quarantine tank. But again, I certainly default to the experts when they come along to offer more advice.
~M