The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Cipangopaludina japonica
Cipangopaludina japonica
(Japanese mysterysnail)

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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

Taxonomy: available through www.itis.govITIS logo

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.

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, 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.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AL196820032Escatawpa; Pickwick Lake
AZ196119611Upper Santa Cruz
CA189220222Sacramento-Stone Corral; San Francisco Bay
DC201720181Middle Potomac-Anacostia-Occoquan
FL194919963Kissimmee; Tampa Bay; Withlacoochee
GA201320232Upper Ocmulgee; Upper Oconee
IL199520183Chicago; Lower Fox; Upper Sangamon
IN196520224Ohio Region; St. Joseph; Tippecanoe; Upper White
KS200520132Lower Smoky Hill; Solomon
MD201420152Middle Potomac-Anacostia-Occoquan; Patuxent
MA191619682Charles; Concord River
MI193719652Great Lakes Region; Upper Grand
MN200720071Lower St. Croix
MS200720071Lower Mississippi-Helena
NE199820202Big Papillion-Mosquito; Salt
NC200420218Deep; Haw; Lower Pee Dee; New River; Roanoke Rapids; Upper Catawba; Upper Neuse; Upper Pee Dee
OH194520224Black-Rocky; Lake Erie; Lower Maumee; Wills
OK195319653Lake Texoma; Lower Cimarron; Middle Washita
PA1962202210French; Lower Delaware; Lower Monongahela; Lower Susquehanna-Swatara; Middle Allegheny-Tionesta; Middle Delaware-Musconetcong; Schuylkill; Shenango; Upper Ohio; Upper Susquehanna-Lackawanna
SC199620176Calibogue Sound-Wright River; Cooper; Lake Marion; Saluda; Upper Broad; Upper Catawba
TX201520151West Galveston Bay
VA200720236Lower James; Lower Potomac; Lower Rappahannock; Middle Potomac-Anacostia-Occoquan; South Fork Shenandoah; Upper New
WI200720164Namekagon; Red Cedar; Upper Chippewa; Upper St. Croix

Table last updated 4/22/2024

† 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.

Impact of Introduction:
Summary of species impacts derived from literature review. Click on an icon to find out more...

EcologicalEconomicHuman HealthOther



This species reaches very high densities, and is considered a nuisance to fisherman; it has been caught in very large numbers by fishermen in Sandusky Bay, Lake Erie, in fact, two tons have sometimes been caught in one seine haul (Wolfert and Hiltunen 1968).

Parasite, Human Health

In the U.S., the Japanese mystery snail has been found to be a regular host to the common native parasite Aspidogaster conchicola, which is a first-time record in North America for a gastropod acting as host to this species (Michelson 1970).

The Japanese mysterysnail is a host to Angiostrongylus cantonensis larvae, a species associated with eosinophilic meningitis (Lin and Chen 1980).

Human Health, Agriculture

The ready ingestion of sewage sludge in rice fields by Cipangopaludina japonica has implications for wastewater treatment problems in urban areas (Kurihara and Kadowaki 1988).

Futher impacts

The Chinese mysterysnail (Cipangopaludina chinensis) is of the same genus as the Japanese mysterysnail; the species are difficult to distinguish from one another morphologically (see 'Remarks' section below; Jokinen 1982), and the Chinese mysterysnail appears to have been studied more heavily for its impacts, which can be viewed here.

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 references)

Burch, J.B. 1980. A guide to the fresh water snails of the Philippines. Malacological Review 13(1-2):121-144.

Cordeiro, J.R. 2002. Proliferation of the Chinese mystery snail, Cipangopaludina chinensis malleata (Reeve, 1863) throughout Connecticut [Abstract]. (R.T. Dillon, ed.) Program and Abstracts of the 68th Meeting of the American Malacological Society, Charleston, SC. p. 37. Available http://www.malacological.org/meetings/archives/2002/2002_abs.pdf

David, A.A., and S.C. Cote. 2019. Genetic evidence confirms the presence of the Japanese mystery snail, Cipangopaludina japonica (von Martens, 1861) (Caenogastropoda: Viviparidae) in northern New York. BioInvasions Records 8(4):793-803. https://www.reabic.net/journals/bir/2019/4/BIR_2019_David_Cote.pdf

Havel, J.E. 2011. Survival of the exotic Chinese mystery snail (Cipangopaludina chinensis malleata) during air exposure and implications for overland dispersal by boats. Hydrobiologia DOI: 10.1007/s10750-010-0566-3. 8pp.

Hirano, T., T. Saito, Y. Tsunamoto, J. Koseki, L. Prozorova, V.T. Do, K. Matsuoka, K. Nakai, Y. Suyama, and S. Chiba. 2019. Role of ancient lakes in genetic and phenotypic diversification of freshwater snails. Molecular Ecology 28(23):5032-5051. https://doi.org/10.1111/mec.15272.

Jokinen, E.H. 1982. Cipangopaludina chinensis (Gastropoda: Viviparidae) in North America, review and update. Nautilus 96(3):89-95.

Jokinen, E.H 1992. The Freshwater Snails (Mollusca: Gastropoda) of New York State. The University of the State of New York, The State Education Department, The New York State Museum, Albany, New York 12230. 112 pp. 

Karatayev, A.Y., L.E. Burlakova, V.A. Karatayev, and D.K. Padilla. 2009. Introduction, distribution, spread, and impacts of exotic freshwater gastropods in Texas. Hydrobiologia 619: 181-194.

Kurihara, Y., and K.I. Kadowaki. 1988. Effect of different ecological conditions on the mud snail Cipangopaludina japonica in submerged paddy soil. Biology and Fertility of Soils 6(4):292-297.

Lin, C.Y. and S.N. Chen. 1980. Epidemiologic studies of angiostrongyliasis in north Taiwan. Medical Journal of Osaka University 31(1-2):7-12.

Mackie, G.L. 2000. Introduction of molluscs through the import for live food. Pp. 305-313 in R. Claudi and J.H. Leach, eds. Nonindigenous Freshwater Organisms: Vectors, Biology and Impacts. CRC Press LLC, Boca Raton, Florida. 464 pp.

Michelson, E.H. 1970. Aspidogaster conchicola from fresh water gastropods in the USA. Journal of Parasitology 56(4):709-712.

Mills, E.L., J.H. Leach, J.T. Carlton, and C.L. Secor. 1993. Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions. Journal of Great Lakes Research 19(1):1-54.

Rivera, CJR.  2008.  Obstruction of the upstream migration of the invasive snail Cipangopaludina chinensis by high water currents.  Unpublished practicum.  Accessed  10/28/13.  http://www3.nd.edu/~underc/east/education/documents/Rivera2008.pdf

Smith, D.G. 2000. Notes on the taxonomy of introduced Bellamya (Gastropoda: Viviparidae) species in northeastern North America. Nautilus 114(2):31-37.

Wolfert, D.R., and J.K. Hiltunen. 1968. Distribution and abundance of the Japanese snail Viviparus japonicus, and associated macrobenthos in Sandusky Bay, Ohio. Ohio Journal of Science 68(1):32-40.

Wood, W.M. 1892. Paludina japonica Mart.fro sale in the San Francisco Chinese markets. The Nautilus 5(10):114-115.

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

Revision Date: 1/20/2022

Citation Information:
Kipp, R.M., A.J. Benson, J. Larson, and A. Fusaro, 2024, Cipangopaludina japonica (von Martens, 1861): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=1046, Revision Date: 1/20/2022, Access Date: 4/22/2024

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.


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Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [4/22/2024].

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