Of course i have, but i have let nature take its course, and 99.9% of the time, the fish gets over it! If a fish is healthy enough, then it will get rid of it on its own! i have maybe lost a total of 5 or 6 fish to ich in the past 12 yrs.. I personally think that is pretty good! Wouldnt you say? I would love to start using a QT but just dont want to deal with the hassle and waiting game of introducing into my mail displays!