I've had 4 snails die but they died before the crabs got to them. After doing a little reading today, I realized that the 4 that died were Astrea snails...I didn't know you had to help them turn back over if they ended up on their backs!!! I know at least 3 of the 4 died while on their backs! Dumb snails!! I don't think I'll be getting any more of those...don't want to spend my day snail-sitting!