The Fascinating Life Cycle of Japanese Trapdoor Snails

Snails can be a beneficial addition to the home aquarium, both for their beauty and their scavenger-style feeding habits. Species like the Japanese trapdoor snail (Viviparus malleattus) are considered invasive in some parts of the world, yet they remain popular in the aquarium hobby.

The Japanese trapdoor snail’s live-bearing reproduction style and conical shells make them an exciting alternative to more common species like the mystery snail and nerite snail. Here’s what you need to know about their life cycle and how to care for them.

Species Snapshot

• Species Name: Viviparus malleattus
• Common Names: Japanese trapdoor snail, Chinese mystery snail
• Size: Up to 2 inches
• Lifespan: 5 to 10 years
• Native Distribution: Japan and other parts of Asia
• Tank Size: At least 10 gallons
• Water Temperature: 68°F to 85°F
• pH: 6.5 to 8.0
• Water Hardness: soft to medium

Like many freshwater snails, Japanese trapdoor snails are relatively easy to care for. The key is to provide ample space for them to graze on algae and other detritus. While these snails breed readily in the home aquarium, they don’t reproduce as quickly as other freshwater snails.

What Do They Look Like?

Japanese trapdoor snails have large conical shells. The whorled shell exhibits a sharp apex with a slightly higher spire. These snails grow to about 2 inches in size and their color is variegated with shades of brown, green, black, and cream. Brown is typically the most dominant color, often seen on the largest whorl of the shell with rings or lines of different colors extending upward.

Like the mystery snail, Japanese trapdoor snails have an operculum – a stiff lid-like structure they can close over the opening of their shell as a protective measure. Nicknamed the trapdoor, the operculum is located on the rear of the snail’s foot. When the snail retracts its foot, the operculum rotates to cover the opening of the shell.

Life Cycle and Reproduction

The Japanese trapdoor snail continues to grow throughout its life, so its size is correlated with its age. That said, diet and calcium levels in the tank affect growth rates. This species is typically sold at sizes between ½ and 1-inch long and it takes about 12 to 18 months for them to reach sexual maturity.

If you don’t plan to breed your Japanese trapdoor snails, it’s best to keep a single specimen or separate them as they approach maturity. While breeding is likely to happen in a tank where both males and females are present, Japanese trapdoor snails don’t reproduce as quickly as other freshwater snails.

Unlike mystery snails, Japanese trapdoor snails don’t deposit large clutches of eggs – they are ovoviviparous breeders. Female trapdoor snails contain developing embryos in a brood chamber where they are protected by their egg capsules until they’re born. Broods range from 1 to 15 baby snails, depending on the female’s size, though it’s common for only one or two to be born at a time.

When they’re born, Japanese trapdoor snails are fully developed – they’re simply smaller versions of the adult snail. Baby Japanese trapdoor snails are about the size of a small pea, and it takes them at least a year to become mature enough to breed themselves. The lifespan of this species depends on diet and environment, but these snails can live as long as 10 years.

Care Tips for Japanese Trapdoor Snails

Like other freshwater snails, Japanese trapdoor snails are very peaceful by nature. They make great additions to the community tank, particularly as members of a cleanup crew. They’ll feed on algae that grows on tank surfaces and eat leftover fish food, decaying plant matter, and other detritus.

Ideal Tank Setup

Japanese trapdoor snails are adaptable to a wide range of tank parameters, so you can feel free to design your tank around other specimens. It is, however, important to ensure that your tank is fully cycled before adding your snails. These snails will thrive in temperatures ranging from 68°F to 85°F, though somewhere in the middle is best. They prefer soft to medium-hard water and pH ranging from 6.5 to 8.0.

To provide plenty of natural food sources, Japanese trapdoor snails are best kept in planted tanks. They will, however, eat algae that grows on just about any surface. A 10-gallon tank may be sufficient for a single snail, but it never hurts to provide extra space. Feel free to decorate with driftwood, rockwork, and other décor elements to make your aquarium more appealing.

Recommended Tankmates

Japanese trapdoor snails are unlikely to cause a problem in the aquarium, though they do best in peaceful community tanks. Their operculum can help protect them from aggressive tankmates, but they may still be prone to predation by large fish like cichlids when they’re small.

Ideal tankmates for this species may include:

• Corydoras catfish
• Barbs
• Small gouramis
• Tetras
• Kuhli loaches
• Danios
• Otocinclus catfish
• Rasboras
• Killifish

These snails can also be kept with other freshwater snails, as long as your tank is large enough. Dwarf shrimp may also be a good fit, though they may compete for food sources.

Diet and Feeding

While adding Japanese trapdoor snails to your aquarium isn’t a substitute for regular tank maintenance, they can certainly help keep things clean. In their native habitat, Japanese trapdoor snails feed on algae, decaying plant matter, and whatever else they can find – the same goes for snails kept in captivity.

Like other freshwater snails, this species is omnivorous, so it will feed on a variety of vegetarian and meat-based foods. To supplement your snail’s intake of algae and detritus, provide a varied diet of algae wafers, sinking pellets, and blanched vegetables.

Other Fun Facts About Japanese Trapdoor Snails

If you know the age of your Japanese trapdoor snails, you can determine their sex by comparing their size. Females are significantly larger than males.

You may be able to estimate the age of your Japanese trapdoor snails by counting the rings on their shells. Differences in shell shape may also help you distinguish between male and female snails of this species.

Japanese trapdoor snails will eat algae off plants and consume decaying plant matter but tend not to feed heavily on the live plants.

Your Japanese trapdoor snails may most active at night and in low-light settings, so keep your lighting on a timer to provide what your plants need without interfering with your snails’ activity. You can get some Japanese trapdoor snails for your tank at Shrimpy business, visit the website now!