Cipangopaludina japonica (von Martens, 1861)

Common Name: Japanese mysterysnail

Synonyms and Other Names:

Japanese mysterysnail, Oriental mysterysnail, Japanese black snail, Japanese trapdoor snail, C. japonicus, C. chinensis japonica, C. chinensis japonicus, Bellamya japonica, B. chinensis japonica, Viviparus japonica, V. japonicus, V. chinensis japonica, Heterogen japonica

Copyright Info

Identification: The genus Cipangopaludina can be identified by its relatively large globose shells and concentrically marked opercula (Burch 1980). Cipangopaludina japonica exhibits a shell with 7–8 whorls, a very narrow umbilicus, and a spire that is produced at an angle of 50–55º (Jokinen 1992). Adult shells display fine carinae, while those of juveniles are covered in hairs on the periostracum where the carinae are located as well as around 8 striae/mm between the carinae in the middle of each whorl (Smith 2000). Individuals are light colored as juveniles and dark brown as adults (Wolfert and Hiltunen 1968).            

The shell of C. japonica grows allometrically, the height increasing faster than the width, and does so at an increased rate in comparison with C. chinensis, so the adult shell is more elongate than that of the latter species (Jokinen 1982). The radula (feeding structure) also may differ between C. japonica and C. chinensis, but there is so much variation even within one species that it is not a good diagnostic characteristic (Smith 2000). However, in one North American population, C. japonica adults' radula had five small cusps on either side of the large central cusp and nine cusps on the marginal tooth (Jokinen 1982).

Size: can reach 50 mm. In Lake Erie, adults range from 30–65 mm high and 22–46 mm wide; females are slightly larger than males when mature (Wolfert and Hiltunen 1968).

Native Range: Cipangopaludina japonica is native to mesotrophic and eutrophic lakes in Japan (Jokinen 1992).  Native to Japan, Taiwan, and Korea.

Great Lakes Nonindigenous Occurrences: Great Lakes:  Japanese mystery snails was found for the first time in Lake Erie in the 1940s (Mills et al. 1993, Wolfert and Hiltunen 1968). There are also some specimens of this species from Green Bay, Lake Michigan from some time before 1968 (Wolfert and Hiltunen 1968).

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Cipangopaludina japonica are found here.

Full list of USGS occurrences

State/ProvinceFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
IN200720081St. Joseph
MI193719652Great Lakes Region; Upper Grand
OH194520223Black-Rocky; Lake Erie; Lower Maumee

Table last updated 11/29/2023

† Populations may not be currently present.

Ecology: The Japanese mysterysnail is known to feed on detritus and sludge, both of which contain a myriad of different types of bacteria (Kurihara and Kadowaki 1988). In Japan, this species is commonly found in rice paddy fields on soil amongst higher plants (Kurihara and Kadowaki 1988).              

Lives in freshwater rivers and lakes.  The Japanese mystery snail in Sandusky Bay, Lake Erie, survives in conditions where surface water temperatures may reach 30ºC, bottom water temperatures can reach 16–24ºC, water is 4 m deep or less, there is high turbidity, the substrate is mud, and aquatic vegetation is sparse (Wolfert and Hiltunen 1968). It sometimes undergoes mortality events in marshes around Sandusky Bay in hot periods when waters dry up (Wolfert and Hiltunen 1968). In general in North America, the Japanese mystery snail has been found inhabiting waters of pH 6.3–7.3, calcium concentration of 11 ppm, sodium concentration of 16 ppm and conductivity of 62–194 μmhos/cm (Jokinen 1992).            

This species is viviparous (Wolfert and Hiltunen 1968), giving birth to crawling young.  Females live up to 8 years and are able to carry 10–120 young (Jokinen 1992). Young are generally born after water temperature rises to 15ºC or more (Jokinen 1992).           

Wolfert and Hiltunen (1968) found that the densities and distribution of the species in a waterbody is influenced by prevailing winds.

This species hosts many parasites, some of which affect human health (Michelson 1970; Lin and Chen 1980).

Means of Introduction: Imported into San Francisco at an Asian food market in 1892 (Wood 1892), and soon after found to be released into the San Francisco Bay, either from accidental disposal of shell or by purposeful release for food production (Wolfert and Hiltunen 1968). Deliberate release into the Great Lakes where it was intentionally stocked as food for the channel catfish, Ictalurus punctatus in Lake Erie in the 1940s (Mills et al. 1993, Wolfert and Hiltunen 1968).

Status: Established in many areas across the eastern US. This species is considered established in Lake Erie and reported from Lake Michigan.

Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...



Current research on the environmental impact of Cipangopaludina japonica in the Great Lakes is inadequate to support proper assessment.

In Spot Pond, Massachusetts, the Japanese mystery snail was discovered to be a regular host to the common native parasite Aspidogaster conchicola, marking the first record for a gastropod host of this species in North America (Michelson 1970). Cipangopaludina japonica may have negative interactions with native gastropods or the environment, possibly similar to those of the closely related C. chinensis (see C. chinensis fact sheet).

Current research on the socio-economic impact of Cipangopaludina japonica in the Great Lakes is inadequate to support proper assessment.

In the past, this species has been caught in large numbers by commercial fishermen in Sandusky Bay, Lake Erie, where two-ton catches have sometimes been reported from one seine haul (Wolfert and Hiltunen 1968). Cipangopaludina japonica has been considered a nuisance by fisherman in this area and could become a similar nuisance in other areas where it exists in dense populations (Wolfert and Hiltunen 1968).

The Japanese mystery snail is a host to Angiostrongylus cantonensis larvae in Taiwan, a species associated with eosinophilic meningitis (Lin and Chen 1980). It is also capable of hosting many other parasites in Asia, some of which may infect humans. The extent of this species’ role as a host to parasites in the Great Lakes is unknown.

Reports of C. chinensis clogging water intakes have emerged, suggesting that closely related C. japonica may also be capable of damaging infrastructure, particularly given the high densities which have been encountered by fishermen in the past (Wolfert and Hiltunen 1968).

Current research on the beneficial effect of Cipangopaludina japonica in the Great Lakes is inadequate to support proper assessment.

Research in Japanese rice paddies suggested that the feeding activity of C. japonica, a common rice paddy dweller and consumer of bacteria, could be used to assimilate excess sewage from wastewater treatments if the sewage were applied as compost (Kurihara and Kadowaki 1988). However, utilizing C. japonicus in such a way could pose a danger to consumers of the snail, including humans, due to the potential accumulation of heavy metals and other toxic substances (Kurihara and Kadowaki 1988).

Mystery snails (Cipangopaludina spp.) have been popular aquarium species in the U.S., and their role in the aquarium/ornamental market is often invoked as the primary explanation of these species’ widespread dispersal (Cordiero 2002, Havel 2011, Karatayev et al. 2009, Mackie 2000, Mills et al. 1993). Cipangopaludina spp. have also had presence in live food markets, particularly in Asian markets of the Western U.S. (Mackie 2000).


Regulations (pertaining to the Great Lakes region)
Japanese mystery snail is a regulated invasive species in Minnesota (MN Administrative Rules, 6216.0260 Regulated)

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Specific control methods for the Japanese mystery snail have yet to be developed – most available control suggestions are based on research with the closely related Cipangopaludina chinensis.

Manipulation of predator fishes and turtles that eat snails may be useful in the control of snail populations.  However, as a relatively large snail species, Cipangopaludina japonica may escape predation by smaller fishes. 

Preliminary research demonstrates that Cipangopaludina chinenesis will not migrate upstream against a small current (Rivera 2008) – it is not known whether C. japonica is similarly restricted.  Acceleration of current may be an important management tool for preventing upstream spread.

Dessication (drying) is not likely to be an effective control method for Cipangopaludina japonica.  Field experiments under mesic conditions indicated that C. chinensis and other snails with opercula can survive exposure to air for at least 4 weeks (Havel 2011).

There are copper compounds that are sold as snailicides but they are usually not selective in the snails they kill. With Japanese mystery snails possessing opercula, more damage would probably occur to native snails in the treatment area than to the target pest.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.

Remarks: Taxonomy of the introduced populations of Asian mysterysnails is confusing and there are many different scientific names in use. There has also been debate regarding whether or not C. chinensis malleata and C. japonica in North America are synonymous and simply different phenotypes of the same species. This database considers the two as separate species. Smith (2000) argues that Cipangopaludina is a subgenus of Bellamya; however, because most North American literature does not use the genus Bellamya to refer to these introduced snails, the mysterysnails discussed here are referred to by Cipangopaludina

Heterogen japonica is used by Hirano et al (2019) based on muliple genetic markers.

David and Cote (2019) did a genetic and morphological analysis on North American populations of both C. japonica and C. chinensis, finding them genetically distinct, morphologically indistinguishable, and co-occuring in multiple lakes of New York; the authors go on to discuss literature which also supports the idea that these two species have no shell characters that can be used to distinguish them morphologically.


References (click for full reference list)

Author: Kipp, R.M., A.J. Benson, J. Larson, and A. Fusaro

Contributing Agencies:

Revision Date: 1/20/2022

Citation for this information:
Kipp, R.M., A.J. Benson, J. Larson, and A. Fusaro, 2023, Cipangopaludina japonica (von Martens, 1861): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI,, Revision Date: 1/20/2022, Access Date: 11/29/2023

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.