Snails reproduce in a variety of ways. Most often it's either fertilized eggs or broadcast spawning. If they have laid eggs, they were already fertilized. As far as I know, some of the egg laying snails in our aquariums are able to store sperm, so even one snail in a tank can have fertilized eggs. It's not often to have snail larvae grow up into even sub-adults. They usually get eaten or starve to death because of lack of food. There's not much you can do about it really.
<a href=showthread.php?s=&postid=10498073#post10498073 target=_blank>Originally posted</a> by capn_hylinur I've had good luck raising the larvae in the refugium--seems like a natural place for them--lots of food and protection