Why the Horned Nerite Snail Won't Breed in Freshwater (Clithon corona)

The Horned Nerite (Clithon corona) lays egg capsules in freshwater, but its larvae require brackish or salt water to develop, so it does not reproduce in a freshwater nano tank.

Overview

The horned nerite, Clithon corona, is a very small Neritidae snail from Southeast Asia, easily recognised by the horn-like projections on its yellow-and-black shell. Its small size suits nano tanks, and it grazes algae while needing hard, alkaline water. Like other nerites it has an amphidromous life cycle in which the larvae need brackish or salt water, so it does not reproduce in a freshwater aquarium.

Sexing

Horned nerites have separate sexes and are not hermaphroditic, so one snail cannot multiply by itself. The sexes are not reliably told apart externally, so a small group is kept to ensure both sexes are present.

Conditioning

These snails stay healthy and lay egg capsules in hard, alkaline water with plenty of algae and adequate minerals. As with all nerites, conditioning the adults does not enable reproduction, because the larvae still require brackish or marine salinity to develop.

Breeding Setup

Completing the life cycle means providing brackish or saltwater for the larval stage. In practice egg-bearing surfaces are moved to a brackish or saltwater rearing tank, or adults are acclimated to brackish water, because the veliger larvae need that salinity and specific gravity to grow into juveniles.

Why It Won't Breed in Freshwater

In freshwater the female lays hard, white egg capsules on surfaces, each containing many eggs, but no viable juveniles emerge. The larvae cannot develop without brackish or marine water, so a freshwater nano tank does not gain new snails even though egg capsules are deposited.

Common Challenges

The hard white egg capsules adhere firmly to decor and glass and are difficult to remove, and many keepers find them unsightly. Even in a brackish rearing tank, the microscopic larvae are very hard to feed, so successful captive rearing is rare.