coral and inverts will be affected. cupramine will not affect your biological filter, when you have a large fish only tank with many large fish you can not remove them. do your research, I have treated large fish tanks with live rock and sand, with cupramine, it takes more than recommended, you need to test and adjust as necessary. If your tank has ick, your tank has ick, not just one fish. You either remove all the fish and let the tank go fallow with no fish, or you will be chasing your tail. As long as there is a fish in the tank there will always be a possible host to continue the cycle of the ick parasite. Depending on your fish population compared to your coral, invert population; people make a decision which is the best way to treat. treating in a quarantine with no rock or sand is always easiest and best to maintain copper levels, but not always possible. Some pull there inverts and coral to another tank. But if you leave apparent unaffected fish in your tank and just pull out the fish with signs of ick, it will almost always raise it's ugly head again.
I've also used cuprisorb and other methods to absorb the copper afterwards, and have always been able to remove the copper, either way it takes time.