Chinese Mystery Snail
Photo credit: Missouri Department of Conservation, Bugwood.org
(Cipangopaludina chinensis malleata)
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Species at a Glance
The Chinese mystery snail is a large freshwater snail commonly sold for use in freshwater aquariums and garden ponds. Its popularity in the aquarium industry has contributed highly to its spread across the United States.
The shell reaches 6.5 cm (2.6 in) in height. It is smooth, strong, and spherical with 6-7 convex whorls separated by prominent sutures, and fine vertical and horizontal lines that are slightly indented. Color is usually dark olive-green for adults and lighter for juveniles. Some adults are greenish-brown, brown, or reddish-brown. The outer lip of the shell is round or oval-shaped and black. An oblong-shaped operculum (or “trap door”) displays concentric growth rings and allows the snail to close the opening of the shell when water conditions are unfavorable or when predators attack.
The native brown mystery snail (Campeloma decisum) has a width to height ratio smaller than the Chinese mystery snail, making it much smaller and narrower with less convex whorls. The introduced banded mystery snail (Viviparus georgianus) is generally smaller (up to 3.5 cm [1.4 in] in height) and has prominent dark horizontal bands. The Chinese mystery snail is also often misidentified as the Japanese mystery snail (Cipangopaludina japonica), which many consider the same species.
The Chinese mystery snail inhabits shallow, quiet waters of lakes, ponds, marshes, irrigation ditches, and slower portions of streams with some vegetation and muddy or sandy substrate.
Introduction of the Chinese mystery snail probably occurred through the aquarium industry and importation for Asian food markets. Once in a body of water, it can be spread by recreational activities via bait buckets and water holding areas on boats.
While native to southeastern Asia and eastern Russia, the Chinese mystery snail was introduced to the United States in the 1890s and into the Great Lakes basin in the 1930-40s. It now occurs widely in the United States and Pennsylvania, including Lake Erie and the Schuylkill and Susquehanna Rivers.
Note: Distribution data for this species may have changed since the publication of Pennsylvania's Field Guide to Aquatic Invasive Species (Second Edition 2015), the source of information for this description.
Chinese mystery snails can serve as vectors for transmitting parasites and diseases, and are a known host for some parasites that can infect humans. They can also clog water intake pipes and compete with native snails for food and resources.
Information for this species profile comes from Pennsylvania's Field Guide to Aquatic Invasive Species (Second Edition 2015).