Japanese Trapdoor Snail
Cipangopaludina japonica
Animalia›Mollusca›Gastropoda›Viviparidae
📍 Japan, China & Russia Far East
The Japanese Trapdoor Snail is a large, attractive freshwater snail with a smooth, olive-green to dark-brown rounded shell and a distinctive calcareous operculum (trapdoor) that seals the shell opening when the snail retreats. It is a peaceful, slow-moving scavenger and algae grazer well suited to ponds and large aquariums. Unlike mystery snails, it is livebearing and gives birth to miniature snails without an egg-laying stage.
Care Guide
Diet
Japanese Trapdoor Snails are omnivorous scavengers that primarily consume algae, biofilm, and detritus from surfaces. Supplement their diet 2-3 times weekly with blanched vegetables (zucchini, spinach, lettuce) and sinking algae pellets or spirulina tablets. They will also consume decaying plant matter and leftover fish food, making them excellent cleanup crew members.
Behavior
These snails are slow-moving, peaceful grazers that spend most of their time crawling along substrate and surfaces searching for food. They are primarily nocturnal and will retreat into their shells, sealing the opening with their distinctive operculum (trapdoor) when threatened or stressed. They are solitary and do not interact with other snails, though they coexist peacefully in community settings.
Breeding
Japanese Trapdoor Snails are livebearers that reproduce slowly and do not produce the population explosions common with other freshwater snails. Females give birth to fully-formed miniature snails without an egg-laying stage, typically producing only a few offspring per year. Breeding in captivity is possible but occurs naturally without special conditions; population control is rarely a concern.
Tank Mates
Peaceful algae-eaters with identical water requirements and non-aggressive behavior
Small, peaceful schooling fish that occupy mid-water column and ignore snails
Peaceful invertebrates with similar water parameters; may compete for algae but coexist well
Peaceful, slow-moving fish that won't harass snails in planted or spacious tanks
Peaceful schooling fish with compatible water requirements and non-predatory behavior
Common Diseases
Shell Erosion
Pitting, thinning, or deterioration of shell surface; white chalky patches on shell
Increase water hardness (8-20 dGH) with calcium supplements or crushed coral; ensure adequate mineral content in water for shell maintenance
Parasitic Infections
Lethargy, reduced feeding, visible parasites on body or shell, mucus buildup
Perform 25% water changes; quarantine affected snails; treat with copper-free parasite medication; improve water quality and tank hygiene
Bacterial Infections
Cloudy shell, soft tissue decay, foul odor, snail refusing to emerge from shell
Improve water quality with frequent partial water changes; remove decaying food and waste; maintain ammonia at 0 ppm and nitrate below 20 ppm
Nutritional Deficiency
Slow growth, thin or weak shell, reduced activity and feeding
Provide varied diet with blanched vegetables and calcium-rich foods; supplement with quality sinking pellets; ensure adequate mineral content in water
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Tanks keeping this 🐟
Kept by 2 hobbyistsCommunity tanks featuring Japanese Trapdoor Snail.
Quick Facts
- diet
- Herbivore/Omnivore – algae, detritus, blanched vegetables, sinking pellets
- breeding
- Livebearing; slow reproduction; does not overpopulate
- lifespan
- 5–10 years
- max size
- 5 cm (2 in)
- tank size
- 10 gallons minimum; outdoor ponds suitable
- temperament
- Peaceful
Water it likes
- ph
- 7.0–8.0
- ammonia
- 0 ppm
- nitrate
- <20 ppm
- hardness
- 8–20 dGH
- temperature
- 39–82°F (4–28°C)