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Japanese Trapdoor Snail
Cipangopaludina japonica
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Photo by Anonymous · CC BY-SA 4.0
Passport
- Family
- Snails
- Grows to
- 7 cm (2.8")
- Lives
- 5–10 years
- Temperament
- Peaceful
- Care
- Beginner
- Swims
- On the bottom
- Keep
- One is fine
- Water
- 18–25 °C (64–77 °F)
JapanChinaSouth Korea
Care requirements
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On record for Japanese Trapdoor Snail: adult size, lifespan, minimum tank, temperature, ph, hardness, carbonate hardness, minimum group, diet, care level, swim level.
Not on record for Japanese Trapdoor Snail: tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 38 L / 10.0 US gal
- pH 7–8
- Hardness 6–18 dGH
- Carbonate hardness 4–8 dKH
- Diet omnivore / algae eater
Care notes written from general aquarium knowledge, not from the cited sources.
About
Trapdoor snails carry a door. The operculum is a hard plate on the foot that seals the shell completely when the animal withdraws, and it's the feature the common name is built on — it protects them from predators and from drying out in a way most aquarium snails can't manage.
They're pond animals as much as aquarium ones, and they handle cold. A trapdoor snail will overwinter in an outdoor pond under ice, which makes them one of very few options for an unheated tank or a goldfish setup.
They're also unusually well behaved for a snail. They eat algae and detritus, they leave plants alone, and they breed slowly enough that they never become the problem a ramshorn or bladder snail can.
Tank setup
Give your trapdoor snails a soft substrate and plenty of grazing surface. They spend much of their time working over the bottom and will partly bury themselves.
Keep the water hard. The shell is thick and the operculum is calcified too, so the calcium demand is real, and soft acidic water erodes both.
Temperature is refreshingly flexible. They're comfortable from cold pond conditions up into the low tropical range, which makes them one of the few invertebrates that suits a coldwater tank.
They're not climbers in the way apple snails are, so an air gap and a tight lid matter less here.
Feeding
Trapdoor snails graze algae, biofilm and detritus and are genuinely good at it. In an established tank they'll find most of their food.
Supplement in a clean tank. Blanched vegetables, algae wafers and calcium-rich snail foods keep them in condition, and an animal this size will run short in a spotless setup.
They're slow, deliberate feeders. Fast fish will strip anything before the snails arrive, so put food down where they are or feed after lights out.
Avoid: copper in anything, and avoid keeping them somewhere with no algae and no supplementary feeding.
Filtration and flow
Gentle to moderate flow suits them. They're heavy and stay put.
Keep hardness up. Everything about snail shell health comes back to available calcium, and a thick-shelled species needs more of it.
Ordinary filtration otherwise. They're tolerant of a wide range and a useful animal in a pond filter box as well as a tank.
With plants
Trapdoor snails are safe with living plants and will leave them alone. They graze the algae off leaves and eat dead material.
This is the main practical difference from most pond snails, which will strip soft plants once their numbers rise. Trapdoors don't.
They're heavy enough to flatten delicate carpeting plants by crossing them, which is mechanical rather than dietary damage.
Health
Shell erosion in soft water is the usual problem, showing as a whitened, flaking spire.
A sealed snail is not necessarily a dead one. The operculum shuts tight when they're resting or unhappy, and they can stay closed for a long time — smell is the test.
They're sensitive to copper and to sudden chemistry change like any snail, but they're otherwise among the toughest invertebrates available.
Breeding
Trapdoor snails are livebearers with separate sexes, so they give birth to fully formed miniature snails rather than laying eggs.
That combination keeps the population sane. Broods are small, growth is slow, and you need both sexes, so there's no prospect of the explosion a hermaphroditic egg-layer produces.
The young are hardy from birth and need nothing special. They graze the same surfaces as the adults and simply take a long time to reach full size.
Tank mates
Avoid9
- Clown Loach Clown Loach is not safe with Japanese Trapdoor Snail: loaches and botia and snails are a bad pairing.
- Demasoni Cichlid Demasoni Cichlid is not safe with Japanese Trapdoor Snail: african cichlids and snails are a bad pairing.
- Dwarf Chain Loach Dwarf Chain Loach is not safe with Japanese Trapdoor Snail: loaches and botia and snails are a bad pairing.
- Electric Yellow Lab Electric Yellow Lab is not safe with Japanese Trapdoor Snail: african cichlids and snails are a bad pairing.
- Hillstream Loach Hillstream Loach is not safe with Japanese Trapdoor Snail: loaches and botia and snails are a bad pairing.
Only with care13
- Chinese Algae Eater Chinese Algae Eater is aggressive and Japanese Trapdoor Snail is peaceful.
- Convict Cichlid Convict Cichlid is aggressive and Japanese Trapdoor Snail is peaceful.
- Jewel Cichlid Jewel Cichlid is aggressive and Japanese Trapdoor Snail is peaceful.
- Bristlenose Pleco Bristlenose Pleco is a risk to Japanese Trapdoor Snail: bristlenose catfish and snails are a pairing to watch.
- Clown Pleco Clown Pleco is a risk to Japanese Trapdoor Snail: bristlenose catfish and snails are a pairing to watch.
No conflict is recorded with the other 82 species in the database, so nothing to flag. 4 species are not covered at all, so they could not be judged either way.