- Location
- The Big City
The reason that some fish can seem to fight it off is because of how a lot of reef tanks are setup. Everything from high flow, overflows, filter bags, and corals and things that eat the Ich spores can have a play in keeping the Ich population down in a tank. Because these things do help the population from booming, after the Ich falls off, fish don't get as infected again, or in some case not at all. Also, over time some fish do develop immunity against the Ich, or just can live with much lower infestations of it. Then again there are some strains of Ich that just wipe out tank very quickly.