Japanese Trapdoor Snail Care Guide - Setup, Diet & Breeding

The Japanese Trapdoor Snail is a large freshwater snail with a rounded, olive, brown or yellow-brown shell, often marked with darker bands or growth lines. Its shell has a smooth to lightly ridged surface and a distinctive operculum, or hard trapdoor, that closes the opening when the snail retracts.

Cipangopaludina japonica is native to East Asia, especially Japan, Korea and parts of eastern China and Russia. It inhabits freshwater lakes, ponds, wetlands and slow-moving waterways, and has also become established outside its native range through human introduction.

A single Japanese Trapdoor Snail is best kept in an aquarium of at least 75 litres, with larger groups requiring more space and filtration. Aim for a footprint of roughly 75 x 30 cm or larger so the snail has broad areas to forage. Use smooth sand or fine gravel, sturdy plants, driftwood and rocks, leaving open surfaces for grazing and avoiding sharp decor that could damage its soft body. The aquarium must be tightly covered because these snails may climb above the waterline.

Adults can reach about 6 cm (2.4 in) in shell length, with females commonly growing larger and heavier than males. Exceptional individuals may approach 7 cm (2.8 in).

These snails graze on algae, biofilm, decaying plant matter and fine organic debris across hard surfaces and the substrate. They should also receive sinking foods such as algae wafers, vegetable-based tablets and softened vegetables when natural growth is insufficient. A reliable source of calcium is important for maintaining the shell.

Japanese Trapdoor Snails are peaceful and can live with calm community fish such as small rasboras, tetras, danios, livebearers and peaceful corydoras. They are also generally compatible with other non-aggressive freshwater snails and larger, peaceful shrimp. Avoid loaches, pufferfish, cichlids, crayfish and other animals that bite, prey on or repeatedly harass snails.

Japanese Trapdoor Snails have separate sexes and reproduce through internal fertilisation, giving birth to live, fully formed young rather than laying visible egg clutches. Females can retain developing embryos and may release several juveniles over time. A mature male and female are needed for breeding, while stable, well-oxygenated water and a calcium-rich environment support shell and juvenile development. Young snails should be protected from fish that may eat them.

Females are usually larger and more robust than males, particularly when carrying developing young. Males tend to be smaller, and their right tentacle is modified for sperm transfer, although this difference is not always easy to see in an aquarium.