Those are some good pictures, although I like the guppies much better than the little snails that can't speak (you did say they are dumb). How did you get the pictures to work? I once had a mystery snail like the one in your picture. A fire belly newt in the aquarium with him tried to chomp on one of the snail's appendages; the snail immediately withdrew into his shell, trapping the newt's head. It was quite a tussle, but everybody survived. Lots of snails are nocturnal, and they will strand themselves on a floating piece of lettuce at night. Maybe they're also kind of stupid in addition to being mute.