Black Japanese trapdoor snails (Viviparus malleatus) are hardy enough to survive cold winters in outdoor ponds. As they are useful in controlling algae growth in aquariums and ponds, it is worth raising them either for your own water feature or for sale. In ponds, Japanese trapdoor snails need virtually no care. They should find sufficient food from the algae, vegetation and aquatic life in the pond and will reproduce without you needing to do anything. In tanks, they need a little care, but not much, especially compared to fish.
Set up a freshwater tank with a low-flow filter and light. These snails are adapted to slow streams and still ponds and don't require fast currents. The light is necessary for the algae the snails feed on. The tank does not need a heater unless you are raising tropical fish at the same time.
Introduce a variety of aquatic plants. They oxygenate the water, help to remove impurities and provide shelter. This species of snail prefers algae to plants, so is unlikely to demolish the plants within a few days.
Introduce a number of snails. Unlike many snails, Japanese trapdoor snails are not hermaphrodites, and they are very difficult to sex. If you want to breed them, you need several to ensure you have at least one male and one female.
Supplement the algae growing in the tank with flaked fish food, live food such as daphnia and fresh vegetables. Japanese trapdoor snails are omnivores and eat a variety of plant and animal foods.
Conduct weekly partial water changes to keep nitrate, ammonia and other toxin levels low.
Test the nitrate and ammonia levels of the tank one to four times a month. Increase the frequency or amount of water changes if levels are high.
Don't keep your snails in the same tank as larger aquarium fish such as cichlids. Aggressive, carnivorous fish are likely to eat the snails, especially the juveniles. Small fish such as tetras and guppies shouldn't be a problem.