I'm an Idiot

[George]

It's true that some fish won't be dead because of ich infection. But that doesn't mean we are not going to do anything to prevent the infection. Ich can be eliminated from a tank if you know its life cycle. A fish can have ich and survive this time, but maybe not next time.
And I don't buy the theory that a fish can have immune to ich. Ich is not a virus or bacteria. it's a parasite and it can attach to anything it get in contact with.