I bought a mystery snail today and wonder if it would be OK to put him in with my fish without quarantining him first. Is it possible for a snail to pass on disease to a fish?
I never qt snails unless they are pond raised or wild snails. I think its pretty unlikely for it to bring anything to your fish. I do know that they have been known to harbor some parasites, but have never had an issue myself. I think flaringshutter had an instance of them transmitting some sort of parasite.
I did have a flukes/nematodes problem that I'm currently treating for - but a lot of my snails are from unknown sources, and I keep a lot of species not commonly seen in the hobby.
Brigs shouldn't need a quarantine - they're from breeders at this point and almost certainly safe.