Planorbidae, common name the ramshorn snails or ram's horn snails, is a family of air-breathing freshwater snails, aquatic pulmonate gastropod molluscs. Unlike most molluscs, the blood of ram's horn snails contains iron-based hemoglobin instead of copper-based hemocyanin. As a result, planorbids are able to breathe oxygen more efficiently than other molluscs. The presence of hemoglobin gives the body a reddish colour. This is especially apparent in albino animals.
Viviparidae, sometimes known as the river snails or mystery snails, are a family of large aquatic gastropod mollusks, being some of the most widely distributed operculate freshwater snails.
Lymnaeidae, common name the pond snails, is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila.
Valvatidae, the valve snails, is a taxonomic family of very small freshwater snails with an operculum, aquatic gastropod mollusks.
Acroloxidae, commonly known as river limpets, are a taxonomic family of very small, freshwater snails, aquatic pulmonate gastropod limpet-like mollusks with a simple flattened conical shell in the clade Hygrophila.
Bithynia is a genus of small freshwater snails with an operculum, aquatic prosobranch gastropod mollusks in the family Bithyniidae.
Melanopsidae, common name melanopsids, is a family of freshwater gastropods in the clade Sorbeoconcha. Species in this family are native to southern and eastern Europe, northern Africa, parts of the Middle East, New Zealand, and freshwater streams of some large South Pacific islands.
Pleuroceridae, common name pleurocerids, is a family of small to medium-sized freshwater snails, aquatic gilled gastropod mollusks in the superfamily Cerithioidea.These snails have an operculum and typically a robust high-spired shell.
The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide.
Amnicolidae is a family of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the superfamily Rissooidea.
Neritiliidae is a family of submarine cave snails, marine gastropod mollusks or micromollusks in the clade Cycloneritimorpha.
Pomatiopsidae is a family of small, mainly freshwater snails, that have gills and an operculum, aquatic gastropod mollusks in the superfamily Truncatelloidea.
Acochlidiidae are a taxonomic family of shell-less freshwater gastropods, aquatic gastropod mollusks within the clade Acochlidiacea.
Helicostoa is a monotypic genus of freshwater snail, an aquatic gastropod mollusc in the order Littorinimorpha containing the single species Helicostoa sinensis.
Moitessieriidae is a family of small freshwater snails, aquatic gastropod molluscs in the superfamily Truncatelloidea.
Stenothyridae is a family of small freshwater snails, snails with gills and an operculum, aquatic gastropod molluscs in the superfamily Truncatelloidea.
The Glacidorbidae is a taxonomic family of freshwater snails.
Gabbia is a genus of a freshwater snails with an operculum, aquatic prosobranch gastropod mollusks in the family Bithyniidae.
Rivomarginella is a genus of freshwater snails, gastropod mollusks in the family Marginellidae, the margin snails.
Rivomarginella electrum is a species of freshwater snail, gastropod mollusk in the family Marginellidae, the margin snails.
