Well, that is a very cool thing to hear! I am still pretty new to this hobby, so the fact that something is actually wanting to propogate in my tank is good news. I'm assuming these are pretty common, since I'm not doing anything remotely special in my tank.
So, is there anything I can do to help them not be eaten by all the other snails in the tank? I suppose it could be interesting to have my tank overrun with a few thousand ceriths.