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.

Channa argus
Channa argus
(Northern Snakehead)

Copyright Info
Channa argus (Cantor, 1842)

Common name: Northern Snakehead

Synonyms and Other Names: Amur snakehead, eastern snakehead, ocellated snakehead, snakehead, Ophicephalus argus Cantor, 1842; Ophiocephalus argus kimurai Shih, 1936; Ophicephalus argus warpachowskii Berg, 1909; Ophicephalus pekinensis Basilewsky, 1855.  Courtenay and Williams (2004) provide a larger list, including names used in other languages.

Taxonomy: available through www.itis.govITIS logo

Injurious: This species is listed by the U.S. Fish and Wildlife Service as injurious wildlife.

Identification: A long, thin fish with a single dorsal fin running the length of the fish. Overall color is brown with dark blotches. It has a somewhat flattened head with eyes located in a dorsolateral position on the anterior part of the head; anterior nostrils are present and tubular; dorsal and anal fins are elongated, and all fins are supported only by rays (Courtenay and Williams 2004). Males are darker in color, and have a broader head, as compared to females (Gascho Landis and Lapointe 2010). Juveniles have a similar color and pattern as the adults.

Snakeheads (family Channidae) are morphologically similar to the North American native Bowfin (Amia calva), and the two are often misidentified. Morphological differences used for identification between the two are depicted here. Snakeheads can be distinguished from Bowfin by the position of pelvic fins (directly behind pectoral fins in snakeheads, farther back on body in Bowfin) and the size of the anal fin (elongate and similar in size to dorsal fin in snakeheads, short and much smaller than dorsal fin in Bowfin). Additionally, Bowfin can be identified by the presence of a bony plate between the lower jaws (gular plate) and a distinctive method of swimming through undulation of the dorsal fin. The Northern Snakehead is also very similar to the Burbot (Lota lota), another North American native fish species.

Size: Maximum size exceeds 85 cm (33 inches).

Native Range: China, Russia and Korea (Courtenay and Williams 2004).  More specifically, the northern snakehead is found in the lower Amur River basin, including the Ussuri River basin and Khanka Lake; the Sungari River in Manchuria; and, the Tungushka River at Khaborovsk, Russia. It is native to all but the northeastern regions of Korea, as well as the rivers of China, southward and southwestward to the upper tributaries of the Yangtze River basin in northeastern Yunnan Province (Courtenay and Williams 2004).

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 Channa argus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AR2008202310Big; Cache; L'Anguille; Little Red; Lower Arkansas; Lower Mississippi-Greenville; Lower Mississippi-Helena; Lower White; Lower White-Bayou Des Arc; Upper White-Village
CT201720171Outlet Connecticut River
DE201020236Brandywine-Christina; Broadkill-Smyrna; Chincoteague; Choptank; Delaware Bay; Nanticoke
DC200520242Middle Potomac-Anacostia-Occoquan; Middle Potomac-Catoctin
FL200020001Upper St. Johns
IL200420041Lake Michigan
LA202320231Lower Mississippi-Natchez
MD2002202315Chester-Sassafras; Choptank; Conococheague-Opequon; Gunpowder-Patapsco; Lower Potomac; Lower Susquehanna; Middle Potomac-Anacostia-Occoquan; Middle Potomac-Catoctin; Monocacy; Nanticoke; Patuxent; Pokomoke-Western Lower Delmarva; Severn; Tangier; Upper Chesapeake Bay
MA200120233Blackstone River; Charles; Merrimack River
MS201720234Big Sunflower; Lower Mississippi-Greenville; Lower Mississippi-Helena; Lower Yazoo
MO201920241Lower St. Francis
NJ200920234Cohansey-Maurice; Crosswicks-Neshaminy; Lower Delaware; Middle Delaware-Mongaup-Brodhead
NY200520215Bronx; Lower Hudson; Middle Delaware-Mongaup-Brodhead; Rondout; Upper Delaware
NC200220072South Fork Catawba; Upper Catawba
PA2004202411Brandywine-Christina; Chester-Sassafras; Crosswicks-Neshaminy; Lower Allegheny; Lower Delaware; Lower Monongahela; Lower Susquehanna; Lower Susquehanna-Swatara; Middle Delaware-Mongaup-Brodhead; Middle Delaware-Musconetcong; Schuylkill
VA2004202312Albemarle; Appomattox; Great Wicomico-Piankatank; Lower Potomac; Lower Rappahannock; Lynnhaven-Poquoson; Middle Potomac-Anacostia-Occoquan; Middle Potomac-Catoctin; Pamunkey; Pokomoke-Western Lower Delmarva; Rapidan-Upper Rappahannock; Shenandoah

Table last updated 7/19/2024

† Populations may not be currently present.

* HUCs are not listed for states where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Ecology: Channa argus is an obligate air-breather, capable of survival in poorly oxygenated waters. Although this species prefers to live in stagnant shallow (< 2 m) ponds or swamps with mud substrate or aquatic vegetation and slow muddy streams, it also occurs in canals, reservoirs, lakes, and rivers (Courtenay and Williams 2004). This species does show some seasonal changes microhabitat selection and preference, utilizing deeper water in winter months and shallow areas with macrophytes during the spawning season (Lapointe et al. 2010). It can adapt to a wide range of aquatic environments, as evidenced by the spread of reproducing, introduced populations throughout Asia and Japan. While its optimum maximum air temperature range is 5-16°C (Herborg et al. 2007), the northern snakehead has a wider latitudinal range and temperature tolerance (0 to >30°C, including frost days) than other snakehead species (Dukravets and Machulin 1978, in Courtenay and Williams 2004; Okada 1960). Reduced metabolism and oxygen demand at low temperatures allows this species to survive extended periods of ice cover (Frank 1970, in Courtenay and Williams 2004). Upper salinity tolerances have been experimentally determined to be between 15 and 18 ppt (at temperatures of 15-24°C; NSWG 2006).

In its native range, reproductive maturity is typically reached when fish are 2-3 years old (Dukravets and Machulin 1978), but may occur only after one year of growth in some introduced populations (USACE 2011). In the U.S., northern snakehead spawning has been observed to start by the end of April, peak in June, and continue through August (Gascho et al. 2011). Adult females build circular floating nests from clipped aquatic plants and release their pelagic, nonadhesive, buoyant eggs on top (Gascho Landis and Lapointe 2010). Each spawn can consist of 1300-1500 bright orange-yellow eggs (about 1.8 mm diameter), with up to five spawns occurring within a year. Northern snakehead fecundity can range from 22,000-51,000 in its native range (Amur River basin; Nikol'skiy 1956) to 28,600-115,000 in an introduced population (Syr Dar'ya basin, Turkmenistan/Uzbekistan; Dukravets and Machulin 1978). Both parents guard the nest of eggs from predation and continue to guard the hatched fry for several additional weeks (Courtenay and Williams 2004, Gascho Landis and Lapointe 2010). Depending on water temperature, eggs may hatch in fewer than three days (28 hours at 31°C, 45 hours at 25°C, and 120 hours at 18°C; Gascho Landis and Lapointe 2010). Larvae experience rapid growth after their first two weeks, though overall individual growth rate in North American populations appears to be less than that in both native and introduced Asian populations (Gascho Landis et al. 2011).

Fry initially feed on zooplankton, before moving on to a diet of small insects and crustaceans (e.g., cladocerans, copepods, small chironimid larvae). Juveniles may feed on small fish, including goldfish (Carassius spp.) and roach (Rutilis spp.; Courtenay and Williams 2004). As an adult, the northern snakehead is a voracious feeder (Okada 1960), and its diet may include fish up to 33 percent of its body length (Courtenay and Williams 2004). Adult prey items include loach (Cobitis spp.), bream (Abramis spp.), carp (Cyprinus carpio), perch (Perca fluviatilis), zander (Sander spp.), grass carp (Ctenopharyngodon idella), various catfishes, cray fish, dragonfly larvae, beetles, and frogs.

Although the northern snakehead can survive up to four days out of the water, overland migration is only possible for juveniles (Courtenay and Williams 2004). The rounded body of the adult northern snakehead is not as conducive to overland migration as observed in more horizontally flattened snakehead species.

Means of Introduction: Potential pathway of introduction: Unauthorized intentional release from aquariums or live food markets

According to the Northern Snakehead Working Group (NSWG) of the U.S. Fish and Wildlife Service, northern snakehead likely arrived in U.S. waters by importation for the live food fish market (NSWG 2006). Unauthorized intentional release from this trade, as was the case in the founding individuals of the Crofton pond population in Maryland, continues to be the major mechanism for introduction (Courtenay and Williams 2004). The northern snakehead has become widely popular in ethnic markets and restaurants over the last two decades, such that this species comprised the greatest volume and weight of all live snakehead species imported into the U.S. until 2001 (Courtenay and Williams 2004, NSWG 2006). In Canada, Herberg et al. (2007) identified two watersheds in the Toronto area along Lake Ontario to be at the greatest risk for northern snakehead introduction from the live fish trade; the Rideau River watershed and Cedar Creek watershed (between Lake Erie and Lake St. Clair) posed additional vectors for introduction. Snakeheads’ resilient nature reportedly makes them more desirable than carps for ceremonial release, and some interest in recreational fishing may also exist (Mendoza-Alfaro et al. 2009, NSWG 2006).

Recognized as a highly injurious species, importation and cross-border transport of northern snakehead was prohibited in the U.S. by a 2002 listing under the Lacey Act and has been subsequently banned in Ontario. Nevertheless, cases of northern snakehead for sale in areas where possession is illegal are not uncommon (NSWG 2006). Accidental release during transport of live fish is possible, but its probability is unknown (Mendoza-Alfaro et al. 2009).

Status: Channa argus is established in Delaware, Virginia, Maryland, Pennsylvania, New York, New Jersey, and Arkansas but is not established in California, Florida, Illinois, Massachusetts, and North Carolina where a few individual fish have been collected. However, the northern snakehead was eradicated from the Crofton pond in Maryland where it was oritinally established. The species is well established in the Potomac River and several of its tributaries in Virginia and Maryland (Starnes et al. 2011). Although young fish were found, the status of the Philadelphia population is uncertain. Officials believe fish may have gotten into the lower Schuylkill River and Delaware River in Pennsylvania and see no practical means to eradicate them. In March 2009, the population in Little Piney Creek drainage received an eradication attempt with the application of rotenone to more 700 km of creeks, ditches, and backwaters. However, more snakeheads have been found since this effort (L. Holt, pers.comm.). The population in Catlin Creek, New York was also treated with rotenone.

The northern snakehead’s broad physiological tolerances, capacity to overwinter—including survival under ice, varied and flexible diet throughout at all life history stages, predatory and competitive nature, high fecundity, and parental investment in offspring, give this species a suite of favorable attributes for establishment once introduced. Northern snakehead can adapt to a wide range of aquatic habitats and has been predicted to have high environmental suitability in the northern U.S. and southern Canada, including abundant potential habitat in the Great Lakes (Herborg et al. 2007, Mendoza-Alfaro et al. 2009, NSWG 2006).

Historical imports to the U.S. have come from a wide range of source populations, including Nigeria, Thailand, Indonesia, China, and Korea (NSWG 2006). Orrell and Weigt (2005) found seven unique mitochondrial DNA haplotypes, none of which were shared, among the five U.S. populations they surveyed, indicating separate introduction events and source populations for each. Such high genetic diversity among introduced populations can promote their establishment and spread (Lee 2002, Sanders 2010).

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


Specific impacts are unknown surrounding the Potomac population. These predatory fishes may compete with native species for food and habitat. Juveniles eat zooplankton, insect larvae, small crustaceans, and the fry of other fish. Adult snakeheads feed almost exclusively on other fishes (>97% of diet), with the remainder of their diet composed of crustaceans, frogs, small reptiles, and sometimes small birds and mammals (Courtenay and Williams 2004; Saylor et al 2012). Adult snakeheads show significant diet overlap with largemouth bass (Micropterus salmoides), with both consuming a large proportion of fundulids and other centrarchids in the lower Potomac River (Saylor et al. 2012).

Remarks: There is no evidence that juveniles or adult snakeheads escaped from the Crofton ponds. The northern snakehead has a wider latitudinal range and temperature tolerance than other snakehead species. It also seems to be adaptable to a wide range of aquatic environments, as evidenced by the spread of reproducing, introduced populations in Asia and Japan.

A specimen collected from Lake Wylie, North Carolina, in 2009 was originally identified as Channa argus, but later genetic work combined with a closer morphological analysis determined the specimen to be Channa maculata (NCSM 53258; W. Starnes, personal communication).

References: (click for full references)

Abdel-Fattah, S. 2011. Aquatic invasive species early detection and rapid response—Assessment of chemical response tools. Report prepared for the International Joint Commission, Great Lakes Regional Office, 25 July 2011.

Aladin, N., I. Plotnikov, T. Ballatore, and P. Micklin. 2008. Biodiversity loss in a saline lake ecosystem. Effects of introduced species and salinization in the Aral Sea. Japan International Cooperation Agency: Study Reports: Country and Regional Study Reports: Central Asia and Caucasus. Volume 4.

Chiba, K., T. Yasuhiko, K. Sakai, and Y. Oozeki. 1989. Present status of aquatic organisms introduced into Japan, in De Silva, S.S., ed., Exotic aquatic organisms in Asia—Proceedings of the Workshop on Introduction of Exotic Aquatic Organisms in Asia: Manila, Philippines. Asian Fisheries Society Special Publication 3: 63-70.

Courtenay, W. R., Jr., and J. D. Williams. 2004. Snakeheads (Pisces: Channidae) -- A biological synopsis and risk assessment. U.S. Department of the Interior, U.S. Geological Survey Circular 1251, 143 p.

Flarherty, M. 2008. New York State Department of Environmental of Conservation. Personal communication.

Gascho Landis, A.M., and N.W.R. Lapointe. 2010. First record of a northern snakehead (Channa argus Cantor) nest in North America. Northeastern Naturalist 17(2): 325-332.

Gascho Landis, A.M., N.W.R. Lapointe, and P.L. Angermeier. 2011. Individual growth and reproductive behavior in a newly established population of northern snakehead (Channa argus), Potomac River, USA. Hydrobiologia 661:123-131.

Great Lakes Panel on Aquatic Nuisance Species (GLPANS). 2008. Prohibited species in the Great Lakes Region. Report November 2008.

Holt, L. 2009. Arkansas Game and Fish Commission. Personal communication.

Holt, L., and J. Farwick. 2009. Northern snakehead Channa argus eradication in Piney and Little Piney creeks, Arkansas. Arkansas Game and Fish Commission.

Illinois-Indiana Sea Grant (IISG). 2011. Sea Grant Database of Aquatic Species Regulations. Available http://www.iiseagrant.org/speciesregs/index1.asp?commonName=Northern+Snakehead Accessed 24 October 2011.

Lapointe, N.W.R., J.T. Thorson, and P.L. Angermeier. 2010. Seasonal meso- and microhabitat selection by the northern snakehead (Channa argus) in the Potomac River system. Ecology of Freshwater Fish 19:566-577.

Lee, C.E. 2002. Evolutionary genetics of invasive species. Trends in Ecology and Evolution 17: 386-391.

Northern Snakehead Working Group (NSWG). 2006. National control and management plan for the northern snakehead (Channa argus). Department of the Interior, unpublished manuscript. Available http://www.fws.gov/northeast/marylandfisheries/reports/National%20Management%20Plan%20for%20the%20Northern%20Snakehead.pdf Accessed: 20 September 2011

Odenkirk, J. and S. Owens. 2005. Northern snakeheads in the tidal Potomac River system. Transactions of the American Fisheries Society 134: 1605-1609.

Okada, Y. 1960. Studies of the freshwater fishes of Japan, II, Special part. Journal of the Faculty of Fisheries Prefectural University of Mie 4: 31-860.

Petr, T. and V.P. Mitrofanov. 1998. The impact on fish stocks of river regulation in Central Asia and Kazakhstan. Lakes & Reservoirs: Research and Management 3: 143-164.

Rash, J. 2007. North Carolina Dept. of Environment and Natural Resources. Personal communication.

Riecke, D. 2017. Mississippi Department of Wildlife, Fisheries, and Parks. Personal communication.

Sanders, N.J. 2010. Population-level traits that affect, and do not affect, invasion success. Molecular Ecology 19: 1079-1081.

Saylor, R.K., N.W.R. Lapointe, and P.L. Angermeier. 2012. Diet of non-native northern snakehead (Channa argus) compared to three co-occurring predators in the lower Potomac River, USA. Ecology of Freshwater Fish 21:443-452.

Starnes, W.C., J. Odenkirk, and M.J. Ashton. 2011. Update and analysis of fish occurrences in the lower Potomac River drainage in the vicinity of Plummers Island, Maryland—Contribution XXXI to the natural history of Plummers Island, Maryland. Proceedings of the Biological Society of Washington 124(4):280-309.

U.S. Army Corps of Engineers (USACE). 2011. Northern snakehead. Available http://glmris.anl.gov/documents/docs/ans/Channa_argus.pdf Accessed: 20 September 2011

FishBase Summary

Author: Fuller, P.L., Benson, A.J., Nunez, G., Fusaro, A., and Neilson, M.

Revision Date: 12/31/2019

Peer Review Date: 9/22/2015

Citation Information:
Fuller, P.L., Benson, A.J., Nunez, G., Fusaro, A., and Neilson, M., 2024, Channa argus (Cantor, 1842): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/factsheet.aspx?speciesid=2265, Revision Date: 12/31/2019, Peer Review Date: 9/22/2015, Access Date: 7/19/2024

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.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [7/19/2024].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted.

For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.