Ich on new fish

[goblin072]

I was wondering how long a fish can have ich and not show it. When purchasing new fish I want to put them into a hospital tank for observation. I have heard that some fish can live with ich in good water conditions. This makes me wonder if its possible to purchase a fish that looks good for weeks but when you put them in a display tank they infect the rest of the fish.

Is this why some people copper all their new fish?

I am a bit paranoid about ich now. One fish killed about 5 others in a very short period of time. I never want to see it again in my main tank.

[CarmieJo]

Ich can take up to 6 weeks to go through its lifecycle but the phase that lives on the fish only lasts 3 - 7 days. Check out this new article Reefreaders - Ich (http://www.reefreaders.com/content/view/52/) that has some great slides to show the lifecycle. Reintroducing fish to a tank too soon and giving the parasite a host will allow the ich cycle continue. Some people do automatically copper all their new purchases although I don't believe in treating a disease that may or may not exist. In order to avoid introducing ich or any disease into your display tank QT everything that is alive.