Be vary careful with the copper. Be sure to test it often. It can be fatal to fish if there is too much in the water.
As far as the Ich goes, you are going to have to remove all your fish from the tank and treat them. Ich is a fish only disease. Even though you might not see the Ich on the fish yet, you will in the future. What happens is that a fish brings Ich into your tank. The Ich goes through its lifecycle which includes a reproductive cycle. In this case, the parasite leaves the fish and spawns more parasites on the bottom of your tank, rock, etc. The new parasites then have about 48hours to find a fish to attach itself to or it will die. If there are no fish, there is no chance the Ich can survive.
When the parasite reproduces on the bottom of your tank, it can take up to 3-4 weeks before the parasites hatch. Thats why you cannot put your fish, any of them, back into your tank before 4 weeks.
Good luck. Be patient. Monitor your water quality!