Hi all, my German Blue Rams have been breeding well and I've raised some fry until they're quite large - Slightly larger than my thumbnail. One of them has been blind in his/her left eye for as long as I know, but I've just noticed another one is completely blind! As in they have a grey/white/milky coat over their eyes.

Is this some form of cataract or parasite? As far as I know the new guy is recently blind since he/she is quite large which means he/she has been feeding well until now

Is there anyway to prevent or reverse this? Should I isolate them?