Wait, I got an AT from LA right after x-mas. Is the last fish to be added to my reef. QT'd for 4.5 weeks, no signs of ich. Took a while to get him eating well, and he was very shy. He would have never survived the display. I did not see any signs of ailment so I never treated with Copper. 3 days after adding to the display I noticed two spots of ich on him.
Its possible I missed it in the qt. I kept him under just a floursecent thinking it would be less stress. Should have used the extra t5 to check him over. The other possibility is there was ich in the display though no fish have shown any signs of it and nothing has been added for 6 months, and none ever showed any. I had a PBT almost two years ago that got it in a previous tank that had some of this rock in it. Its possible it got in that way, or maybe a coral. I had not been qt'ing corals. I will start now. Either way, point is do copper once he is eating and healthy. Keep good flow in the qt, keep him eating well, and make sure you treat for it because you may not be able to see it and the only people I have ever read about not having a problem were folks that treated for it either way. I am now in the process of setting up a new sump system so my old sump can be turned into an additional qt (its an old 55 long) and I can qt the entire tank and let it go fallow. Yeah, because I have not read of anyone having a good outcome with their AT by letting him ride it out but 1 person on the long AT thread on this board or on other boards. So, even though he is "fighting it off" and "eating well" and everyone is getting along, and not other fish show signs, odds are, he will not make it. He's been thru three bouts of the cycle now almost and its not lessening. I figure I have about a week to get him in qt and start working on it. Can't do just him because it will come right back once I move him....
Sorry for the long post. I planned everything before ordering this fish and thought I was clear. Its my dream fish, and they are awsome, but success seems to hinge on a clean tank and stringent procedures combined with perfect water with lots of movement and oxygen and constant vigilance.
Hope that helps...