Chinese Mystery Snail

Family: 
Viviparidae (large operculate freshwater snails) in the order Architaenioglossa (having gills and often an operculum)
Description: 

The shell of the Chinese mystery snail is large, spherical and smooth. The outer shell is light to dark olive green. The inner shell is white to pale blue. The operculum (“trapdoor”) is concentrically marked, with uniform color throughout, and no banding. The shell can have 6 to 8 whorls. The whorls are strongly rounded, and each suture where the whorls join is very indented. The outer lip is blackish and either round or oval.

Size: 
Shell length: up to 2 1/2 inches
Habitat and conservation: 
You can find these snails in lakes, ponds, rice fields, irrigation and roadside ditches and calm portions of streams where there is a soft mud substrate.
Foods: 
Chinese mystery snails feed on algae, zooplankton and phytoplankton.
Distribution in Missouri: 
Found in at least 11 counties in Missouri.
Status: 
Invasive.
Life cycle: 
This snail stays partially buried in the mud where water is slow. The females give birth to live, crawling young. A female can give birth to 169 young or more in a lifetime, and a single brood may have 102 young. Females can live up to five years, where males only live to about three. This species of snail has an operculum, which is like a “trap door” that allows them to close their shells when water conditions are harsh.
Human connections: 
Mystery snails have been imported to our country by the aquarium industry as well as for Asian food markets. Some releases were probably from hobbyists, and others may have been deliberate in an effort to create a local food source. They can transmit diseases to humans and clog water intake pipes.
Ecosystem connections: 
Chinese mystery snails can serve as vectors for the transmission of parasites and diseases to our native aquatic species. They also compete with our native snails for food and space.