The Japanese Trapdoor Snail is a gastropod that inhabits mesotrophic and eutrophic lakes. It’s commonly found in countries like Japan, Korea, and Thailand. Nonetheless, the popularity of this mollusk species is gaining in North America due to its non-temperamental nature and tank-cleaning habits.

If you’re interested in reading up on Viviparus Malleattus as a potential occupant of your aquarium — then this guide’s just what you need. We’ve compiled all essential details relating to housing and caring for this freshwater snail species with input from experts and vetted data.

Japanese Trapdoor Snail: Quick Figures

Family Buccinidae
Care Level Beginner
Average Lifespan Five to 10 years
Maximum Size 2 inches
Diet Omnivore
Breeding Type Live-bearing
Minimum Tank Size 10 gallons

Japanese Trapdoor Snail: Appearance and Temperament

Japanese Trapdoor Snails are also famously known as Japanese Mystery Snails and Chinese Mystery Snails. However, it’s their scientific name that hides clues about their appearance. Here’s how.

– Appearance

The term “malleattus”, from Viviparus Malleattus, means hammered or beaten. It’s an ode to the species’ globe-like shells with concentric whorls that look like someone’s taken their time shaping them. Generally, the hard body of a Japanese Trapdoor will contain approximately three to four whorls, with a very slight umbilicus or hole at the center.

In the wild, the structure of their shells helps protect the species from predators looking for an easy meal. Any loud noise or sudden movements in its vicinity will cause this freshwater aquarium snail to tuck inside its protective cover for refuge.

Surprisingly, these snails are light-colored as juveniles but tend to darken as they age. If you’re lucky enough to care for a Japanese Trapdoor juvenile, you’ll also notice that its shell will grow faster in length, as opposed to width. Overall, these snails make a welcome addition to any freshwater aquarium, thanks to their curvilinear appearance.

– Color Varieties

While aquarists might not have too many options when it comes to variety in shape, you’ll have plenty of choices in terms of shell color — from Black Japanese Trapdoor Snails to green and brown ones. However, cream-colored Trapdoor snails are more of a rarity.

Folks who want their community fish tank to have a colorful appearance will be happy to learn that a Japanese Trapdoor Snail’s shell isn’t entirely in one uniform shade. You’ll observe that the species’ shells tend to lighten towards the top, and many snails will also feature attractive textural lines that add to their looks.

– Temperament

Behavior-wise, Viviparus Mellattus are non-aggressive and tend to mind their own business. Although, if you think that you’ll barely see any movement from this species thanks to their origins, you can’t be more mistaken.

Japanese Trapdoor Snails are pretty active. You’re likely to see them moving from one end of the tank to the other, searching for algae and other organic matter to feed on. They won’t go whizzing past other tank mates, but they are indeed interesting to observe.

It’s also just as common for these little guys (or gals) to tuck themselves away in their shells for some me-time. That doesn’t mean they’re ill or depressed. Instead, it’s just a part of their natural behavior.

Fish keepers with Japanese Trapdoors are also advised to cover their tanks at night or when they leave the house for long hours. It’s not uncommon for these wily snails to wriggle all the way up to the top of the tank in curiosity.

How to Care For Japanese Trapdoor Snails

Japanese Trapdoor Snails in aquariums won’t generally require too much care. Nonetheless, we’ve covered details about the species diet, water and tank parameters, and habitat details in this section to help prospective buyers get a better idea about what their maintenance requires. Here you can find some more details.

– Diet Specifics

If you remember, we mentioned that Japanese Mystery Snails are native to mesotrophic and eutrophic lakes. But what are they? Allow us to explain.

Mesotrophic and eutrophic are classifications of a water body. Mesotrophic lakes generally contain clear water with aquatic plants and medium-level nutrients. On the other hand, eutrophic lakes include an abundance of aquatic plants and have high levels of nutrients — especially nitrogen and phosphorus. They’re also teeming with organic matter and algae.

In short, both types of lakes are perfect for the dietary habits of Japanese Trapdoors. You see, this snail species has a great liking for waste generated by other underwater organisms and algae. However, they’re actually omnivorous in nature. That means your Japanese Mystery Snail will require you to feed it, despite having ready-made food options in the tank.

Japanese Trapdoor Snails do well with live food, frozen food, plant and bottom-feeder pellets. In short, they’re not very picky when it comes to their dining options.

At times, hobbyists are tempted to overfeed other fish because they think the Japanese Trapdoors will take care of the leftover feed. But that’s definitely not a good idea. Overfeeding fish means you’ll have to clean your tank more often to control ammonia levels. Additionally, it can also cause other aquatic species to suffer stress, which in turn can affect their immunity and lifespan.

– Tank and Water Parameters

On their own, Japanese Trapdoors don’t really need a lot of space, and a 10-gallon tank ought to work just fine for this species. However, if you’re planning on introducing these snails to a community aquarium, your source of concern should be water parameters and habitat requirements.

Even though Japanese Trapdoor Snails look hardy, it’s not uncommon for them to die suddenly after being introduced to a new tank. Experts suggest this might have to do with the stress of being moved or inadequate water conditions of the home tank.

That’s why it’s best to ensure you’ve got the water settings of your established tank in order before adding these snails in. Viviparus Malleattus do well in water temperatures of 69 to 88 F. They also require soft to medium water hardness and pH levels ranging between 6.5 to 8.

It’s best to monitor the water condition of your aquarium for a few days after the addition of Japanese Trapdoor Snails. Doing so will help you keep the tank conditions stable until the snails acclimate to their new surroundings.

– Habitat Details

We’re aware that hobbyists without other fish species will have more options as far as deciding on tank habitat goes. However, the good news is that Japanese Trapdoor snails don’t require too much to keep them happy.

Since these freshwater snails will spend a majority of their time on the bottom of the tank, it’s best to start by considering the kind of substrate you will add. Remember that snails move by inching or dragging themselves across a surface. That’s why it’s best to change out your rougher substrate for a sandier one to keep things safe.

Snails can suffer cuts from the uneven edges of a hard substrate, leading to infections and illness. However, fish keepers planning on introducing Japanese Trapdoors to their community tank are advised to get a separate tank instead of changing the substrate, because this can significantly impact the tank’s ecology.

Another tip is to have plenty of aquatic plants (such as Anubias) in your tank. Remember, the Viviparus Malleattus come from lakes with plenty of flora, which is a source of nourishment for them. You can also add rocks, wood, and other such structures to collect algae that the snails can snack on.

It’s also not wise to depend entirely on Japanese Trapdoors to do away with your tank’s waste material. You’ll need to fit your tank with a good quality filter to keep the water clean. However, don’t forget to cover filter intakes to keep your snails from getting stuck in the filters and suffering injuries.

Viviparus Malleatus Stats: Lifespan, Growth Rate, and Size

When talking about aquatic wildlife stats, it’s impossible not to touch upon lifespan, growth rate, and size. That’s because these numbers can heavily influence a hobbyist’s opinion about a new species. If you’re curious about how long Japanese Mystery Snails live or how big they can grow, then this section is for you.

– Japanese Trapdoor Snail Lifespan

A Japanese Trapdoor Snail’s life expectancy ranges between five to 10 years. However, as always, we’d like to remind our readers that general lifespan guidelines are just that. They’re not 100 percent accurate and can be affected by various factors, such as disease, stress, etc.

However, on the whole, if you take good care of your Japanese Trapdoors and their immunity’s strong enough to ward off infections, you can expect your gastropods to keep you company for a long time, both in fish and human years.

– Japanese Trapdoor Snail Growth Rate

It’s impossible to accurately chart the rate at which Japanese Trapdoors grow because it’s not something experts or fishkeepers are keeping track of. However, the size of these snails is linked to their age, which means the older a Japanese Trapdoor Snail is, the bigger it is likely to be.

– Japanese Trapdoor Snail Size

Despite how humongous Japanese Trapdoor Snails appear in pictures, they’re actually known to grow up to 2 inches in height and about 1.8 inches in width. Juvenile Japanese Trapdoors can measure between ⅛ to ¼ of an inch. This makes them pretty small compared to popular freshwater aquarium wildlife.

Japanese Mystery Snail Breeding Specifics

If you’re looking for information to breed Japanese Trapdoor Snails, the good news is that it’s pretty easy to do. Unlike the uncertainty surrounding the species’ growth rate, getting Japanese Trapdoors to breed in freshwater aquariums is problem-free.

Their name, “Viviparus Malleattus”, holds a clue about their reproduction characteristics. They’re live-bearing snails, which means you don’t have to worry about them laying eggs on the substrate that could become prey to other fishes in the tank.

What’s more, the gestation period of Japanese Trapdoors is about nine months, which means overpopulation isn’t a concern either. You don’t have to take any measures to interfere with their reproduction for fear of having your community tank overrun by mollusks.

Generally, these freshwater snails reach the age of reproduction at 18 months and can give birth to approximately 20 snails in one go. Once the snails are born, the female Trapdoors (you can identify them through their longer tentacles) will remove the membrane surrounding the young.

– A Few Precautions To Take When Breeding

Fishkeepers won’t need to move Japanese Trapdoors to a separate tank to breed them. Nor will you have to create a specific environment to get them to reproduce. That’s one of the things that makes this freshwater mollusk species so popular with hobbyists: there’s no extra effort involved in breeding them.

The only thing you need to be careful about is the nitrate levels of the water. Japanese Trapdoors can experience stress when the nitrate levels exceed 40ppm and can die because of it. Excessive nitrate is not only a danger when it comes to breeding, but can also potentially put their lives at risk.

It’s also essential for you to know how to sex Japanese Trapdoors for breeding purposes. Sexual dimorphism in the species is easy to identify, thanks to their difference in size. Female snails are larger than their male counterparts. However, you may have to wait until the snails are at least a year of age to be able to figure out their sex.

There isn’t much of a difference between males and females when it comes to shell shapes. The easiest way to tell female snails apart from male ones is by observing their tentacles. Female Japanese Trapdoors have two tentacles that are straight in appearance. Conversely, the right tentacle of male Japanese Trapdoors is shorter and slightly curved.

Japanese Snails Health Considerations

Aside from the Japanese Trapdoors’ sensitivity to nitrate, they’re pretty hardy and will live a long and healthy life with good care. Another sensitivity you should know about is copper, and even the slightest traces of copper can lead to Japanese Trapdoor Snail poisoning.

Once the snails’ systems absorb the copper, there’s not much to be done. Their system can either overcome the situation or die. You should be mindful of the kind of medications you’re introducing to your fish tank and ensure that none of them include copper.

These snails are susceptible to certain common illnesses and infections, which is why it’s best to refer to a suitable veterinarian, specialized in aquatic species, if you see your Trapdoor behaving strangely.

Japanese Trapdoors beyond the age of five years are prone to developing edema, which causes fluid to build up in their bodies. There’s not much hobbyists can do if their snails develop the condition, except wait and watch how the snail responds.

Tank Mates for Japanese Trapdoor Snails

Japanese Trapdoor Snails are unassuming and peaceful creatures who like keeping to themselves. They’re not at all aggressive and are incredibly easy-going, which is why they make excellent tank mates for a variety of freshwater aquarium species.

They also tend to do well in a wide range of freshwater settings because they’re pretty forgiving as far as temperature, pH, and water hardness levels are concerned.

Japanese Trapdoors get along swimmingly with Bamboo and Blue Velvet Shrimps. They also do well with fishes such as the Celestial Pearl Danio, Bristlenose Pleco, Ember Tetra, etc. Just keep in mind that Japanese Trapdoors don’t get along too well with Assassin Snails because of their carnivorous nature.


Japanese Trapdoor Snails are popular freshwater mollusk species due to their algae-eating and non-temperamental nature. However, the species are considered invasive and can be illegal to keep in some areas.

  • Here are some of the highlights related to their characteristics, care, and maintenance:
  • The species have globe-like shells with concentric whorls and a very slight umbilicus or hole at the center.
  • Japanese Trapdoors are pretty uniform in shell shape (though females are slightly larger) and are available in black, green, and dark brown colors. Cream-colored snails are somewhat rare.
  • Behavior-wise, the Viviparus Mellattus are non-aggressive and tend to mind their own business. However, they’re also active for their species and like moving around the bottom of the tank.
  • This snail species has a great liking for waste generated by other underwater organisms and algae. However, they’re actually omnivorous in nature.
  • They do well with live food, frozen food, plant and bottom-feeder pellets. In short, they’re not very picky when it comes to diet.
  • Viviparus Malleattus require water temperatures of 69 to 88 F, medium water hardness and pH levels ranging between 6.5 to 8.
  • For tank habitat, add soft substrate with plants and rocks and wood.
  • A Japanese Trapdoor Snail’s life expectancy ranges between five to 10 years.
  • Juvenile Trapdoors measure 1/8 to 1/4 of an inch, whereas adults can grow upto 2 inches.
  • The species are live-bearing snails and have a gestation period of 9 months. The snails are easy to breed and can deliver upto 20 snails in one go.
  • Japanese Trapdoors get along with a variety of freshwater aquarium species, however, fishkeepers should avoid housing them with Assassin Snails.

After this extensive guide, you can finally take care of your Japanese Trapdoor Snail in the best way!

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