Why the Tiger Nerite Snail Won't Breed in Freshwater (Neritina turrita)
The Tiger Nerite (Neritina turrita) lays white egg capsules in freshwater, but its larvae require brackish or salt water to develop, so it does not reproduce in a freshwater aquarium.
Overview
The tiger nerite, Neritina turrita, is a Neritidae snail from Southeast Asia, recognised by a golden-orange shell crossed by dark stripes. It is an effective algae grazer that does best in hard, alkaline water. Like other nerites it has an amphidromous life cycle that depends on brackish or salt water for larval development, so it does not reproduce in a freshwater aquarium.
Sexing
Tiger nerites have separate sexes and are not hermaphroditic, so a lone snail cannot multiply. External sex differences are not reliably visible, so keeping several snails together is the usual way to ensure both sexes are present.
Conditioning
Hard, alkaline water with plentiful algae and adequate minerals keeps adults in good condition and prompts egg-laying. Conditioning alone does not lead to reproduction, however, because the larvae still require brackish or marine salinity to develop.
Breeding Setup
Completing the cycle requires moving the larval stage into brackish or saltwater conditions. In practice the egg-bearing surfaces are transferred to a brackish or saltwater rearing tank, or adults are acclimated to brackish water, since the veliger larvae need that salinity and specific gravity to develop 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 they do not yield viable snails. The larvae cannot complete development without brackish or marine water, so the tank population does not grow even though egg capsules appear regularly.
Common Challenges
The hard white egg capsules adhere stubbornly to decor and glass and are widely regarded as unsightly. Even in a brackish rearing tank the microscopic larvae are very hard to feed, so successful captive rearing is rarely achieved.