What is "ramshorn snail"

The term ramshorn snail is used in two different ways. In the aquarium trade it is used to describe various kinds of freshwater snails whose shells are planispiral, meaning that the shell is a flat coil. Such shells resemble a coil of rope, or (as the name suggests) a ram's horn. In a more general natural history context, the term "ramshorn snails" is used more precisely to mean those aquatic pulmonate gastropod mollusks in the family Planorbidae that have planispiral coiled shells.

This article is about ramshorn snails in the aquarium trade. For more information on the Planorbidae, see the article Planorbidae.

Ramshorn snails have been bred for the aquarium trade and various color forms have been selected. Most of the aquarium ramshorn snails are species in the family Planorbidae, but one kind is from a totally different family, the Ampullariidae.

Ramshorn snails can sometimes become a nuisance in an aquarium, because some of them breed so profusely.