No rapid breathing at all. Even when others were impacted by ich, he's been chill. Eyesight is definitely fine. He sees me from across the room. Yes, he was eating great in the 125.That's a tough call! No rapid breathing seen? Are you sure the angel's eyesight isn't affected? If you wave your hands outside the tank, does it react? If not, then I would worry about that, but if it shies away, then eyesight isn't the issue. At this point, since the fish *had* been feeding and now it is not, combined with no other symptoms, I would consider moving it into a better environment, one with a stable biofilter and no copper.
Jay