I think my post was misunderstood. I qt all my new fish and even inverts once the tank is established. I don't believe that because it is hard you shouldn't try [emoji22]. I was saying that if you were to sample every drop of your aquarium water you would most likely find you missed/accidentally got contaminated with a less virulent strain somewhere down the line. Unless you have certain fish like ford pointed out you would have no idea. Yes it is possible to avoid but you need rigorous qt protocols and treatment procedures on EVERYTHING. Snails, hermits and corals can introduce it into a tank. I know people who follow this but the majority don't and everyone makes mistakes. So I am not advocating not trying I just ment I take people claiming their dt is completely ich free with a grain of salt.