Chinese mystery snails are small animals with a coiled spiral shell. They grow up to three inches tall and are olive colored. The shell opening is on the right when the shell is pointed up. They have an operculum (”trapdoor”) covering the opening, which is missing when the snail is dead and the shell is empty.
The Chinese mystery snail grazes on lake and river bottom material. They are called “mystery” snails because females give birth to young, fully developed snails that suddenly and “mysteriously” appear. Their lifespan is about four years. These snails can die off in large numbers and wash up on shore.
Origin and Spread
The Chinese mystery snail is native to Asia. The species is commonly imported and sold by the aquarium trade, leading to the potential for illegal release into the wild. It was brought to California in 1892 as a food source, and found in Massachusetts in 1915. Populations were first recorded in Minnesota in the early 2000’s. Refer to EDDMapS Midwest for distribution information.
Don't be fooled by these look-alikes
- Banded mystery snails (invasive)
- Faucet snails (invasive)
- New Zealand mudsnails (invasive)
- There are a number of snail species native to Minnesota. Contact the DNR for more information on native snails.
The Chinese mystery snail (Cipangopaludina chinensis) is a regulated invasive species in Minnesota, which means it is legal to possess, sell, buy, and transport, but it may not be introduced into a free-living state, such as being released or planted in public waters.
Threat to Minnesota Waters
Invasive species cause recreational, economic and ecological damage—changing how residents and visitors use and enjoy Minnesota waters.
Chinese mystery snail impacts:
- Can die-off in large numbers, fouling beaches and shoreland.
- In Asia, it can transmit human intestinal flukes, however, no cases have been documented in the United States. It is also a carrier of trematode parasites found in native mussels.
What you should do
People spread Chinese mystery snails primarily through movement of water-related equipment and illegal release of aquarium pets. It is illegal to release or dispose of unwanted aquatic plants or animals in or near public waters. Refer to Habitattitude for alternatives to release. Young Chinese mystery snails can be as small as a grain of rice. Adults and young, which may be hidden in mud and debris, can stick to anchors and ropes as well as scuba, fishing, and hunting gear. The snails’ operculum allows them to close their shells and survive out of water for multiple days.
Whether or not a lake is listed as infested, Minnesota law requires water recreationists to:
- Clean watercraft of all aquatic plants and prohibited invasive species.
- Drain all water by removing drain plugs and keeping them out during transport.
- Dispose of unwanted bait in the trash.
- Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.
There is no known effective population control for Chinese mystery snails in natural water bodies at this time.