I find threads like this very interesting. First of all, let me emphasize that I am a huge proponent of QT'ing. I do it with all of my fish. After months of reading about ich and the best way to treat fish in QT for it, I choose the tank transfer method. I tried some of the others (Hypo, copper etc.) but killed fish doing it so they weren't for me.
But I completely understand the inability for some to be able to do it, either because of space constraints, time or whatever else people have reasons for not doing it. Plus I also completely understand the unwillingness to empty a display tank for 3-4 months. But here is a truth: If you look back at all the fish that people have talked about on here that have died, I bet you'd see more have died in QT than from ich. If someone does not have a standing QT protocol and a system to deal with sick fish, then I would also recommend garlic and trying to boost immune function rather than try a QT set up that they've never done before. But I would also encourage them to research proper QT'ing and if at all possible implement it in the future. Yes, I know ich would still be in the tank, but there are far worse illnesses out there for fish than ich. Marine velvet to name one.
Anyways, not that anyone asked for it, but that's my $0.02
