So my DT got ich and it infected just about all the fish in the tank pretty quickly. At the time I had a Blue Chromis in my QT. I managed to get one of my clowns out of the tank, put him in the QT with the Chromis and treated with copper according to the directions. The clown died after 3 days. My tank is about to go fallow once I get the last fish out. Question is, if my chromis is still healthy at the end of the 72 day period in my QT, do I risk reintroducing ich back into the display because he was roommates with the clown for a few days or will the copper treatment take care of it? Thanks.