Zebra Nerite Snail Breeding Guide

Zebra nerites lay white egg capsules in freshwater, but their larvae need brackish or saltwater to develop, so they cannot multiply in a freshwater aquarium.

Overview

The zebra nerite, Neritina natalensis (also placed in the genus Vittina), is an algae-grazing snail of the family Neritidae endemic to the coastal plain of East Africa, including Kenya, Mozambique, Somalia, South Africa and Tanzania. In an aquarium the shell grows to about 2.5 cm in diameter, and the snail prefers a temperature of 22 to 26 C.

Sexing

Nerites have separate sexes, but the sexes are difficult to tell apart externally. Because the snail cannot complete its life cycle in freshwater, sexing is largely academic for the home aquarist.

Why It Won't Breed in Freshwater

Nerites have an amphidromous life cycle: the adults live in freshwater, but they return to brackish or saltwater to reproduce, and they can only reproduce in saltwater or brackish conditions. Females lay eggs that hatch into larvae which can survive only in brackish water, so the larvae cannot develop in a freshwater tank. As a result, despite being popular in the trade, the species cannot successfully breed in freshwater aquariums.

Egg Capsules in the Aquarium

Females will still deposit small white egg capsules on hard surfaces such as glass, rocks and decorations in a freshwater tank. These capsules are harmless but will not hatch into surviving young, because the larvae require brackish or marine water. This is also why nerites do not overpopulate a freshwater aquarium.