Pond shells are inhabits in rivers, ponds, and waterfalls around the world. Most shells (pondshells) are shaped like a horn shaped shell. These species sometimes are confused to be related to marine snails, but don`t be fooled. Marine snails are more colorful and have more shapes. A common river/pond shell shell is the pond snail. Picture is seen below. However, this species can clean aquariums very well, yet over populate.