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Japanese Trapdoor Snails: Complete Trap Door Snails Guide

The Japanese Trapdoor Snail is a peaceful, relaxed, freshwater aquarium addition that helps manage the algae growth and excess organic matter in its habitat. Its name is derived from the hard operculum that covers and protects it when it retracts its body into the shell. It closes like a trapdoor making its body inaccessible to predators while maintaining its moisture.

They are wonderful and attractive maintenance additions to large, freshwater tanks and outdoor ponds. These are truly fascinating shelled gastropods with some keen talent for cleanliness and the demeanor of the nice, old lady down the road who bothers no one and asks for nothing. But she’ll genuinely smile at you whenever you glance her way.

Let’s learn more about the fascinating, beautiful Japanese Trapdoor Snail!


As a species, the Japanese Trapdoor Snail has gone by various names over time including; The Japanese Mystery Snail, The Black Snail, Asian Apple Snail, Rice Snail, and the Chinese Mystery Snail. Its scientific classification is Viviparus malleattus.

They are native to East Asia from the tropical areas of Indo-China, mainly China, Japan, Myanmar, and Thailand, through eastern Russia and are classified as pond snails.

Its “trapdoor” is a hard operculum that snaps shut and seals the shell which protects the snail from dehydration and predation. This feature is common to most snails. It is considered a large snail with gills that prefers bodies of freshwater that have muddy or silty substrates. The soft bottom is much easier on the snail’s delicate body.

Life Span

The female of the species has a slightly longer lifespan at an average of 5 years while the male of the species lives an average of 3-4 years. However, it is common for both sexes to live about 1 year in captivity due to variations and unexpected changes in their habitat. Conversely, some have been purported to live 5-10 years in a healthy, captive, well-maintained environment.

While they are mostly disease resistant, Japanese Trapdoor Snails are susceptible to oedema, a fluid build-up in tissue. This can sometimes occur in older snails. For now, the only known treatment is to keep an eye on the situation to see if the affliction continues. And copper is extremely toxic to them. Make sure the water is not tainted with any copper.

This is important because many water additives and medications for fish can contain copper as an ingredient. Be sure to ask about copper before adding anything to the water with your gentle friends.

Sudden death, shortly after purchase, is not uncommon due to a variety of possible reasons including rough handling during transport, a shift in the water quality and content between the store and home, and sometimes just an individual snail’s sensitive nature.

It is advised to make any transition as gentle and stress-free as possible. Allow the snail to gradually adapt to its new environment with patience.

Japanese Trapdoor Snail Appearance
Japanese Trapdoor Snail Appearance


Typically, the base color of the Japanese Trapdoor Snail is brown. It is usually complemented by 3 or more whorls of color, with 3 whorls being the most common.

The primary whorl, closest to the base, is usually one color. As it progresses to the taper of the shell, the color whorls are often varied between green, black, cream, and a reddish-brown that become lighter in color as they advance higher up the shell.

The color combinations can vary considerably, and some shells will taper to a sharp point. The Japanese Trapdoor Snails are tan, black, or cream in base often have brighter colors. And the majority of the shells are usually lightly textured with thin ridges that are the snail’s growth lines. It is not unusual for the shell to have large white spots at the top of the shell near the apex.

The females have long antennae-like tentacles which likely help the birthing process when they remove membranes from the freshly birthed snails. The males have shorter antennae. The inner color of both female and male shells is white to pale blue.

Japanese Trapdoor Snail Size
Japanese Trapdoor Snail Size


The standard maximum size of the Japanese Trapdoor Snail is 2 inches. Though there have been instances where they have been found to be larger, some reportedly being 3 or 4 inches. Many for purchase average about 0.5 to 1.5 inches in length. The 2 inches makes them one of the largest breeds of freshwater snails for aquarium hobbyists. And females are often twice as large as males.

The big guy in your tank is probably a big girl. She’s got to house all of the living embryos during the breeding season.

Care and Habitat Requirements

Considering their native habitats in silty ponds and lakes, it is best to have the floor of the aquarium or pond covered in a softer, somewhat sandy, or muddy substrate. This will ensure that the Japanese Trapdoor Snail doesn’t become irritated or injured by a rougher surface.

A rough surface can lead to cuts that can become infected. So gravel or pebble is not a wise choice of base for these cute, little gastropods.

Likewise, it is beneficial to have many real plants and wood or rocks that algae can collect upon. As the plants decay, they provide another food source for the Japanese Trapdoor Snail who will feast upon a variety of decaying, organic matter.

They will not eat the living plants if they have enough food available. So there is no need to be concerned about the aquarium flora when you are properly feeding your snails. The snails will actually keep the water cleaner and clearer for the plants to thrive.

The water in the tank or pond should be kept between 68 to 88 degrees Fahrenheit or 20 to 31.1 degrees Celsius without sudden temperature fluctuations. Sudden changes can shock and kill the snails. The water quality should be soft to medium, never hard. And the ideal pH balance is between 6.5 to 8. The Japanese Trapdoor Snail will thrive in these conditions.

The stable and comfortable environment will also permit your snail a longer, happier lifespan.

Despite the Japanese Trapdoor Snails’ nature as filter feeders that keep the water clean, it may still be necessary to purchase an additional filter if there are live plants or other organic matter in the aquarium habitat. For the snail’s sake and reduction of the possibility of the curious snail becoming trapped in the filter, it is best to cover the intake valve with a coarse sponge material.

It is likewise recommended to have a cover on the top of the aquarium in case your Japanese Trapdoor Snail decides to embark on an adventure over the top of the tank. Since they sometimes seek shallower water, this is known to happen from time to time.

The aquarium itself should be no less than 10 gallons to ensure the snails have enough space to forage and grow. This is a relatively small tank, but the tank size will likely be more dependent on any other companion fish requirements since the size requirements for the snail are minimal.

Though they do need enough room to explore. They can cover a considerable amount of ground in a day scouring for sustenance.

Dim lighting and darker areas or corners are beneficial for the nocturnal feeders too. Playing around with the lighting to provide some shadier spaces for the Japanese Trapdoor Snails would be a great kindness to them. A very bright tank may deter their feeding and shorten their life span.

Food and Diet

As stated previously, the main food of the Japanese Trapdoor Snail is algae and plant detritus. But these adorable little animals are omnivores that will also eat greens and proteins. It would be wise to supplement their diets with plant-based pellets and bottom-feeder tablets. And they will eat things that have been frozen.

This makes it possible to accessorize their diets with blanched vegetables like kale, cucumbers, zucchini, spinach, and lettuce. They enjoy foods that are rich in Calcium.

Just don’t overfeed the snails or companion fish. Despite their reputation as filter feeders, it is possible to put in too much food that will end up clouding the water and making all of the aquarium inhabitants ill. And contrary to common belief, they do not eat fish excrement. And many fish do not know when to stop eating.

So an excess of food can produce an excess of waste that will be ignored by the waste management snails and will cloud the tank water requiring more work from the human purveyor of the freshwater world. Just like with our own diets, they need proper proportions.

Japanese Trapdoor Snail Temperament
Japanese Trapdoor Snail Temperament

Behavior and Temperament

Japanese Trapdoor Snails are the perfect neighbors! They are very peaceful in nature desiring only to eat and breed. They are symbiotic helpers while being completely unaware of their important role. So you’ll never catch them bragging about their stellar work or slacking off because a neighbor is lazy.

Despite being considered slow and inactive, they are nocturnally inclined. It is likely you will see them become active most often if you are up at night also. They’ll get to work cleaning the tank while most of their tank mates are sleeping.

They don’t bother the other fish or even each other really. They truly are ideal neighbors. So researching fish that won’t eat or irritate your snails is encouraged. You’ll get a sense if they are being bothered if you see them in their shells often, especially at night.

It is typical for them to hide out in their shells for long periods as the shell mainly serves as protection and their foraging keeps them fairly active. A consistently hiding snail is indicative of some level of unhappiness or possibly illness. Expect these mollusks to be on the move regularly.

Japanese Trapdoor Snail Tank Mates
Japanese Trapdoor Snail Tank Mates

Tank Mates

Japanese Trapdoor Snails are great in groups of their own. They are often sold in groups of 10-20 snails as they live together in the wild also. Because they are so adaptable and pleasant, they do well with a wide variety of fish. Some freshwater creatures that do very well with the snails are:

  • Sulawesi Snails
  • Rummy Nose Tetra
  • Otocinclus
  • Killifish
  • Kuhli Loach
  • Nerite Snails
  • Pearl Gourami
  • Honey Gourami
  • Ghost Shrimp
  • Ember Tetra
  • Harlequin Rasbora
  • Cory Catfish
  • Bee Shrimp
  • Bamboo Shrimp
  • Amano Shrimp
  • Blue Velvet Shrimp
  • Bristlenose Pleco
  • Cherry Barb
  • Cherry Shrimp
  • Congo Tetra
  • Celestial Pearl Danio
  • Ivory Snails
  • Gold Inca Snails
  • Trumpet Mystery Snails
  • Viper Shrimp
  • Wood Shrimp
  • Ramshorn Snails

A good neighbor welcomes almost everyone without being overbearing. And the Japanese Trapdoor Snail fits the bill. Just try to avoid partnering them with rougher fish like cichlids, goldfish, and aquarium crayfish. They may harass your Japanese Trapdoor Snails creating a stressful environment that will impact the happiness and survivability of the sweet-natured snails.


Japanese Trapdoor Snails are a live-bearing species. This means that the embryos develop inside the eggs inside the female snails. In the wild, the young are born in shallower waters and eventually migrate to deeper waters.

Because they are live-bearing, they have a longer gestation period of about 9 months. So you do not have to worry about them over-running your tank or pond-like some snail species that procreate rapidly and in abundance.

They typically birth from 6 but up to 20 snails per cycle and the female uses tentacles (antennae) to remove the membranes around the newborn snails. There is no need for a special tank as breeding will happen naturally with both sexes present in a healthy, stable environment.

So this is an effortless breeding process for humans, if you want a lot of these snails, just be prepared to wait out the gestation period. And if possible, provide varying water levels so the Japanese Trapdoor Snails can follow their natural process from shallower to deeper waters during their development.

Are Japanese Trapdoor Snails invasive?

Depending on where they are found Japanese Trapdoor Snails can be considered invasive. For instance, states like Michigan, New York Minnesota, Ohio, and Wisconsin are considered invasive in lake settings. This is because they beat out other native species of snail and fish that also eat algae and pi ant detritus.

The food competition has made them illegal to be released into the wild in some places, like the states listed above since they can negatively impact the food sources for other animals. And if they run out of algae or plant decay to ingest they will begin to eat the freshwater plants that are vital to other life in the water bodies. They could also potentially wipe out some plants over time.

But because they do take longer to gestate and do so in smaller broods, they are not as dangerous as some other invasive species that can procreate more rapidly or can reproduce asexually.

Burrowing Japanese Trapdoor Snail
Burrowing Japanese Trapdoor Snail

Do Japanese trapdoor snails burrow?

The short answer is “no”. The full answer is they might look like they do. The Japanese trapdoor snail, also known as the Chinese mystery snail, is not only one of the largest snails in the freshwater aquarium hobby, but also one of the most versatile snails you can find for your freshwater tank.

They are algae eaters so they will be wherever algae in your tank can be found. They dwell in all levels of the aquarium and are well-known escape artists, so don’t fill your tank completely to the top.

As they also clean the bottom and substrate of your tank, it may look like they do burrow, but technically they are usually just scavenging for uneaten food or waste, and they do a pretty good job at it. So they might dig a little deeper to get to a yummy food source.


Japanese Trapdoor Snails seems to be a perfect addition to any freshwater, indoor aquarium that has the right water conditions and environment. They help keep the water clean for all of their tank mates and plant life. They are easy to care for and are mainly self-sustaining with the appropriate, well-proportioned food available.

If they are happy and healthy in their homes, they will breed without any effort from a human caretaker. And they are quite beautiful to look at hanging around a tank.

Despite their popularity for outdoor ponds, it would be ill-advised to add them here due to their classification as invasive in many places. And it would be impossible to stop them from migrating from the pond to nearby waterways.

Not to mention, it is more difficult to maintain the integrity and stability of the pond environment versus a tank environment. Like a hunting house cat, keep them inside and don’t set them free for the sake of the surrounding native life.

They are excellent tank mates that do well with a large variety of fish other snails and some crustaceans. Since they are active at night, they feed and clean while most other water dwellers are sleeping. And when well fed, they will keep the plant life happy and healthy too.

Once you understand and attend to the needs of these little filter feeders, you can keep a tank of happy, little rainbow shells that make the tank ’pop’. They are very attractive and helpful little creatures that deserve their accolades for being quiet convivial waste managers. Who doesn’t love a friendly, calm, stylish trash collector?

Please feel free to respond with any comments or questions regarding these delightful, little beasts. Let us know if you have any and what your care routines are.

In summary, Japanese Trapdoor Snails are perfect for most freshwater aquarium tanks. If you’re looking for a filter feeder that does a great clean-up job and is pleasing to the eye these guys are an ideal match. Their pleasant peaceful nature and maintenance skills make them a
Ideal pet.

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