I can't answer for sandwi54; but I just seconded his post. I've been keeping SW fish for 35+ years. For over 20 years, I've had at least 1000 gal. of DTs. Lost them to Katrina, moved, and restocked. That is a hell of a lot of fish. For 11 years, I treated ich-infested fish for a little lfs. I sort of mis-read sandwi54 post ; but I still have treated at least 50 fish with ich symptoms using Cupramine. I Prophylacticly treat all new fish with Cupramine as part of a normal (for me) QT regimen. I haven't seen ich in any of my DTs in many, many years. I buy all of my fish from a couple of online dealers; best fish on the planet, IMO. Any fish, from any source can carry ich. Yes, I've tried other methods. I think there are a couple that work; tank-transfer, and probably CP. If Cupramine doesn't work, I think 99% of the time its due to a preventable error.