Very good point. FWIW I don't use a UV and I QT ALL my fish, and have never had a problem w/ ich or anything else in my main, until a few months ago. When I added a pair of Occ clowns, the smaller was relentlessly harassed. During this time it stopped eating, and developed ich. No other fish in the tank ever did or have since. After soaking foods in selcon, target feeding, and a hierarchy was established between the clowns meaning no more harassment, the ich went away and has never returned. The clowns never showed any signs of ich/illness during a 5 week QT prior to going in my main.timbo2 said:From what I have studied, all aquariums, even the major ones such as Sea World and such have ICH and other nasty buggers present at all times. The main thing to keep in mind is good aquarium husbandry. Making sure that the stress level of the tank is down to bare minimums is always the best precaution.