[marrone]

Quote: Originally Posted by fritz I've always wondered if it was due to the coating on the fish. A mature and very healthy fish should have a nice coating over them that perhaps the ich isn't able to penetrate, or not easily penetrate. A stressed and or weakened fish would not have this coating or at least less of it making it perhaps more susceptible to infection by the parasite and secondary infections. I always figured that was why established fish were never effected by low exposure to ich.

The problem with this is that ich is usually taking in by the mouth, gills and eyes, and then works it way though the fish body. If the fish has a very thick coating the ich mayn't be able to break out, and start the cycle over again. But Eels also get ich and if you ever have picked one up you'll notice they have a very thick coating on their bodies.