Breeding the Orange Rabbit Snail (Tylomelania zemis)
Tylomelania zemis is a Sulawesi rabbit snail that bears a single large live juvenile at a time. This guide covers its dioecious biology, hard alkaline conditioning and slow reproduction in the home aquarium.
Overview
Tylomelania zemis is one of the rabbit snails endemic to Lake Poso on the Indonesian island of Sulawesi. The genus Tylomelania belongs to the family Pachychilidae and is unusual among aquatic snails in being dioecious, meaning individuals are either male or female rather than hermaphroditic. These snails are slow grazers adapted to the warm, hard, alkaline waters of the ancient Sulawesi lakes.
Reproduction is exceptionally slow, so a breeding project requires patience and stable conditions over many months. Because the species is one of several endemic Sulawesi rabbit snails, captive propagation also reduces collection pressure on wild populations.
Sexing
Tylomelania cannot be reliably sexed by external appearance, and a single animal cannot reproduce on its own. The practical approach is to keep a small group so that both sexes are present. Successful births are the clearest confirmation that at least one male and one female are in the tank.
Conditioning
Adults are conditioned with stable water chemistry and steady feeding rather than seasonal triggers. They graze biofilm and algae continuously and benefit from leaf litter as a natural food source. Keep ammonia and nitrite at zero and nitrate low, since traces of these are harmful and soft water can erode the shell over time.
- Temperature: 26-30 °C (79-86 °F)
- pH: 7.5-8.5 (alkaline; avoid soft water)
- GH: 6-14 °dGH
- KH: 4-10 °dKH
- Minimum tank volume: 60 L
Breeding Setup
No special spawning tank is needed; rabbit snails breed in a well-maintained display that mimics their Sulawesi habitat. Provide dim lighting, hiding places and a sand or fine substrate. Hard, warm, alkaline water with high oxygen and excellent water quality is the main requirement for reproduction.
Reproduction & Young
Tylomelania are ovoviviparous livebearers. The pallial oviduct has evolved into a uterine brood pouch that releases a fully shelled juvenile, and the species produces only one large offspring at a time rather than many eggs. Newly released juveniles of some Tylomelania species are nearly 2 cm long, among the largest of any viviparous gastropod, and emerge from a calcareous capsule before grazing independently.
Common Challenges
The principal challenge is the very low reproductive rate, with long intervals between single births. Soft or acidic water causes shell pitting, and unstable temperature or nitrogen spikes stall reproduction. Avoid known snail predators such as loaches, pufferfish and assassin snails.