Faucet snails (sometimes called trapdoor snails) are a small species reaching a maximum of 2cm. They can be easily confused with the young of larger species with an operculum (trapdoor) like Viviparus viviparus. The most notable difference is their small size and ability to lay eggs (most trapdoor snails give birth to live young). They are great algae grazers and will graze algae from rocks, glass and plants (they wont eat live plants) as well as scavenging detritus, dead fish, plants and left over fishfood ,like mussels They also filter algae, bacteria and small particles from the water colum and in decent numbers are excellent at clearing green or murky water. Being a native species, it can survive UK winters but can also be kept in coldwater and tropical aquariums. Snails make up an essential part of a pond or aquarium ecosystem and would make an excellent addition to a wildlife pond.