These are photos of an apple snail, Pomacea bridgesi , provided by someone who visited this site. If you know any of the Latin names for the species that I do not, please e-mail the information to me. A pond is not complete without aquatic snails. If you set out to create a snail-free pond, they will always mysteriously show up. Whether they survived a chemical dip on plants or took a ride on a bird's legs to get there, if you build it, they will come.
Aquatic snails are the clean-up crew for the pond.
Most of them will eat surface algae, small pieces of plants, dead animals, and leftover foods. Some of them will damage plants. Most of them will only improve the overall health of the pond. Snails, along with tadpoles, are often added to eat pond algae. It is rare for snails to overpopulate a pond as they do in aquariums.