Horned Nerite Snail Breeding Guide

Horned nerites (Clithon corona) lay egg capsules in freshwater, but like all nerites their larvae need brackish or saltwater, so they will not breed in a freshwater tank.

Overview

The horned nerite, Clithon corona, is a small snail of the family Neritidae distinguished by horn-like projections on its shell that give it its common name. It is a species of brackish water and freshwater habitats, native to the Western Pacific, from the Philippines to Micronesia, Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia, Samoa, Taiwan and the Okinawa and Ryukyu Islands of Japan. It is kept as an algae-grazing snail.

Sexing

Like other nerites, Clithon corona has separate sexes that are not easily distinguished externally. Because it cannot complete its life cycle in freshwater, sexing has little practical value for the home aquarist.

Why It Won't Breed in Freshwater

Nerites such as Clithon follow an amphidromous life cycle in which the adults live in freshwater but the larvae require brackish or saltwater to develop. Females lay eggs that hatch into larvae which can survive only in brackish water, so in a freshwater aquarium the larvae cannot mature. This is why horned nerites, despite being popular algae eaters, do not reproduce or overpopulate freshwater tanks.

Egg Capsules in the Aquarium

In freshwater the female still deposits small white egg capsules on hard surfaces such as glass, wood and rocks. These capsules will not produce surviving young because the larvae need brackish or marine water to develop.