Ramshorn

Ramshorn refers to freshwater snails in the family Planorbidae. They are named for their shell shape, a flattened, disk-like coil that lies in a single plane, giving a ram’s horn appearance when viewed from the side. Shells are typically brown to tan and can vary in size by species. Most ramshorn snails lack an operculum and breathe air through a simple lung, though they can also exchange some oxygen across their moist body surfaces.

These snails inhabit a wide range of freshwater environments worldwide, including ponds, streams, and wetlands. They have also become common in artificial systems such as aquariums and water gardens, often spreading to new areas via the aquarium trade and shipments of aquatic plants.

Ecology and behavior: Ramshorn snails are detritivores and grazers, feeding on algae, biofilm, decaying plant matter, and leftover foods. They help break down organic material and contribute to nutrient cycling in aquatic ecosystems. In home aquariums, they are valued for cleanup duties but can reproduce rapidly under favorable conditions, potentially leading to population surges and nuisance growth.

Notable species include the great ramshorn (Planorbarius corneus) and the rosy ramshorn (Planorbella duryi), both of which are commonly encountered in hobbyist settings. Identification is aided by the flat, disc-like shell and the absence of an operculum.