I would defintely not add copper to your main tank, it would be best to remove the fish to a qt tank and does it there. Also will take less medicine and be easier to dose. As mentioned , copper can kill inverts.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.