I didn't know they could take on a snail. I do see mine float down out of nowhere to pick up some of the worms I feed to my young crays and fish. It's really got to be spooky for the worms, this thing shows up out of nowhere, picks them up, swims away and then MUNCH they're toast. Haha. Hmm, maybe I'll dump some of my pond snails in to see what happens, heh.