|
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. |