Not furry either, still lovely.
Japanese Trapdoor Snail
Sinotaia quadrata histrica
Also called Himetanishi (Japanese), Bellamya aeruginosa (synonym used in China), Trapdoor snail
From East Asia. The species Sinotaia quadrata ranges across China, northern Vietnam, Japan and northeast Thailand; Japanese populations belong to the subspecies histrica.1
At a glance the quick version
Adult shell height 20-30 mm for Sinotaia quadrata; LiveAquaria gives up to 2 inches (about 5 cm) for the snail sold under this trade name.
Looks how to spot one
Rounded spiral shell with an operculum (trapdoor)
A sturdy, conical shell that is taller than it is wide. A hard lid on the foot can close the opening like a trapdoor, and the snail breathes with a gill.12
Personality what they are like
A placid, slow grazer that keeps to itself, cleaning surfaces of algae and debris without bothering fish or plants much. Best kept away from snail-eating tankmates.2
Daily activity how busy a day looks
Slow and steady; spends its time grazing over glass, decor and the bottom.12
Grooming and care the hands-on bits
Low-maintenance and hardy. Provide clean water and something to graze; it is tough enough for outdoor ponds in many climates.21
Home where they are happiest
Ponds or aquariums of at least 10 US gallons with a soft or muddy bottom and some plants. Wild populations tolerate about 6-30 C, breeding best at 24-26 C; LiveAquaria suggests 20-29 C (68-85 F), pH 6.5-8.0 and 5-12 dKH.12
Food basics what goes in the bowl
Grazes and deposit-feeds on algae films, diatoms, bacteria and detritus; in captivity it also takes vegetables, fish food and other prepared foods.12
Company who they like around
Fine in groups. Sexes are separate and females give birth to live, shelled young, around 50 per year, so a small group slowly grows.12
The story where it all began
Sinotaia quadrata has long been part of daily life in East Asia, sold as food in Chinese markets, cooked in Thai dishes and used as feed in aquaculture. Japanese pond keepers and aquarists value it as a hardy algae grazer, and it has also turned up outside its home range in Italy and Argentina.1
Fun facts for the dinner table
- 1
A single female can produce around 50 live babies in a year, and a new generation can mature in about four months.1
- 2
In some lakes these snails reach densities of up to 400 per square metre and help shape water quality.1
- 3
Newborns are only about 3-3.7 mm long and wider than they are tall.1
- 4
It is hardy enough to survive outdoor winters in many northern ponds.2
Recognised by the official bits
- Taxonomy
- Two subspecies are recognised, S. q. quadrata and S. q. histrica. The trade name Japanese trapdoor snail is also applied in shops to other viviparid snails, for example LiveAquaria lists it as Viviparus malleatus.1
- Aquarium trade (LiveAquaria)
- Sold under the name Japanese Trapdoor Snail; described as live-bearing and hardy.2
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Japanese Trapdoor Snail. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amountsevery day
- Temperature checkevery day
- Water changeSmall, gentle water changesevery week
- Water testevery week
- Filter rinseRinse in old tank water, never tap waterevery month
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- Sinotaia quadrata - Wikipedia en.wikipedia.orgused for origin, subspecies, size, reproduction, diet, temperature range, history
- Japanese Trapdoor Snail - LiveAquaria liveaquaria.comused for aquarium care, water parameters, colours, temperament
Checked 2026-09-30. Text is written in our own words from these sources.