Ramshorn Snail Breeding Guide

Planorbarius corneus is a hermaphroditic freshwater snail that lays gelatinous egg masses on plants and glass; a single individual can found a population.

Overview

The great ramshorn snail, Planorbarius corneus, is a flat-coiled freshwater snail of the family Planorbidae found in ponds, rivers and canals. Its shell typically measures about 35 mm in diameter. As a pulmonate it can breathe air at the surface, and its blood contains hemoglobin, which lets it cope with low-oxygen water; it is a dietary generalist. It can live up to about 6 years in captivity.

Hermaphroditic Reproduction

Ramshorn snails are hermaphrodites, so sexing is not required: each individual has both male and female organs. Self-fertilization is possible, meaning a single released animal can establish a stable population on its own.

Eggs & Young

The snail lays gelatinous egg masses on aquatic plants such as Elodea and Ceratophyllum, as well as on the glass walls of a tank. The masses are cylindrical or oval and average about 12 by 8 mm. Each egg mass contains roughly 12-49 light-yellow eggs, and by one account up to 60. Eggs begin hatching within about 31-65 days of being laid. The species follows a yearly reproduction cycle.

Common Challenges

Because the snails are hermaphroditic and self-fertile, a colony can grow from a single animal, so population control is the usual concern. Note that under some lab conditions only about 5 percent of self-fertilized juveniles hatch, so output varies with conditions and food availability.