Two-Ridge Ramshorn (Helisoma anceps) Breeding Guide

Helisoma anceps is a hermaphroditic North American ramshorn that lays underwater egg masses of about 20 to 30 eggs. Warmer temperatures trigger mating.

Overview

Helisoma anceps is a North American ramshorn-style snail of the family Planorbidae, ranging widely across the continent and inhabiting lakes, ponds and streams where it favours littoral silt and detritus. The species name anceps means two-sided, referring to its ridged shell. It typically lives two to three years and reaches 8 to 16 mm in shell diameter.

Sexing

The species is hermaphroditic, so each individual carries both male and female reproductive parts and pairing for specific sexes is unnecessary. Mating in related planorbids is induced by encounters with other individuals and by rising temperature.

Conditioning

Reproduction in this snail is seasonal, likely in spring and summer, and warmer water encourages mating. Female reproductive output rises with the quantity and quality of food, so a steady supply of algae and detritus supports egg production.

Egg-laying / Reproduction

After mating, the snail attaches gelatinous egg masses to underwater substrates such as rocks, stones or aquatic plants. Each mass contains about 20 to 30 eggs, and the gelatinous coating protects the developing embryos from predation and infection. The snail provides no parental care after laying.

Juvenile Care

Juveniles hatch directly from the egg mass and immediately graze on bacteria, protists, algae and detritus using the radula. In dense populations egg-mass production declines, which helps limit overpopulation in a closed aquarium.