Channa striata - Common Snakehead

Channa striata (Bloch, 1793)

Common snakehead

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Figure 1: Live adult specimen of the common snakehead (Photo: Eric Er; used with permission)

Distribution

The common snakehead has a wide natural distribution ranging from tropical Southern Asia to most of Southeast Asia Chaudhry, S. Channa striata. The IUCN Red List of Threatened Species 2010: e.T166563A6237224. 2010 [cited 2015 9 September]; Available from: http://www.iucnredlist.org/details/166563/0

]]>Courtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]> (Figure 2), including Singapore. In parts of Southeast Asia where it is not native (i.e., the Philippines, Sulawesi, and Papua), it has established as an alien species following introduction as a food fish.

Figure 2: Native and introduced distribution of the common snakehead Channa striata (after Chaudhry, 2010Chaudhry, S. Channa striata. The IUCN Red List of Threatened Species 2010: e.T166563A6237224. 2010 [cited 2015 9 September]; Available from: http://www.iucnredlist.org/details/166563/0

]]>; Courtenay & Williams, 2004Courtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>)

Habitats

Within its native range, the common snakehead is widespread throughout lowland regionsLee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>. It can be found in shallow (< 1 m), stationary/slow-flowing waters thick with bank vegetation (Figure 3A). This species is highly adaptable, and can be found over a relatively wide range of temperatures and pHLee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>. As such, the common snakehead can also be found in artificial habitats such as ponds, canals, padi fields Lim, K.K.P. and P.K.L. Ng, A Guide to the Freshwater Fishes of Singapore. 1990, Singapore: Singapore Science Centre.

]]>Baker, N. and K.K.P. Lim, Wild animals of Singapore. 2012, Singapore: Draco Publishing & Nature Society (Singapore). 180.

]]>Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(Figure 3B). In Singapore, it can be found in streams of the Central Catchment Nature Reserve, and occasionally seen in monsoon drains and artificial ponds.

Figure 3: An open-canopy stream within the Central Catchment Nature Reserve, Singapore (A) and artificial pond habitat, Sungei Buloh Wetland Reserve, Singapore (B), where the common snakehead may be found (Photos: Kenny W.J. Chua)

Physical appearance

Adult
Although the exact colour may vary, the live adult common snakehead can be distinguished from most other adult snakeheads by its relatively plain colour pattern, lacking distinct spots or blotches Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(Figure 4). When compared with the similarly plain-coloured black snakehead (Channa melasoma), the common snakehead can be identified by the presence of (at times subtle) dark diagonal stripes on its dorsal surface, a more abrupt transition between dorsal and ventral colour patterns, and the absence of a thin white margin to the caudal and dorsal finsNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(Figure 5). Lower jaw morphology also differs between the two species. In the common snakehead, the sides of the lower jaw are either parallel or converge towards the snout, whereas the jawline diverges slightly in the black snakehead Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(Figure 6).

Figure 4: Compared to most other snakeheads that are found in Singapore, the adult common snakehead lacks bold patterns and colours (from A to D: dwarf snakehead (Channa gachua), forest snakehead (Channa lucius), giant snakehead (Channa micropeltes), common snakehead (Channa striata) (Photos: A—Kenny W.J. Chua; B—reproduced from siamensis.org, 2011siamensis.org. Channa lucius. siamensis.org: Thailand Nature Explorer 2011 [cited 2015 14 Nov]; Available from: http://www.siamensis.org/species_index - 2445--Species : Channa lucius.

]]>under Creative Commons BY-NC-SA 4.0); C—reproduced from siamensis.org, 2011 siamensis.org. Channa micropeltes. siamensis.org: Thailand Nature Explorer 2011 [cited 2015 14 Nov]; Available from: http://www.siamensis.org/species_index - 2455--Species : Channa micropeltes.

]]>under Creative Commons BY-NC-SA 4.0); D—Tan Heok Hui, used with permission)

Figure 5: Comparing the common snakehead (Channa striata; A) and black snakehead (Channa melasoma; B) (Photos: Eric Er (A), Tan Heok Hui (B), used with permission; annotations added by Kenny W.J. Chua)

Figure 6: Jawline morphology of the common snakehead and the black snakehead; the common snakehead has a jawline that converges towards the snout, while that of the black snakehead is slightly divergent (after Ng & Lim, 1990Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

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Body proportions of the common snakehead also differ from the black snakehead. Postorbital head length is between 28.6–37.2%; interorbital width is 5.1–8.9%; preopercular length ranges between 6.2–26.4%; pelvic-anal distance ranges from 3.5–8.8%; caudal length is 11.9–23.3% (measurements are in percentage of standard length) Lee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>(Figure 7).

Figure 7: Morphometric measurements commonly used for diagnosing snakeheads (Illustration: Kenny W.J. Chua)

Juvenile
Juvenile snakeheads differ in appearance from adults. The larvae of most species have orange/red and black longitudinal bands that fade as the fish matures. However, the young of the common snakehead and the dwarf snakehead (Channa gachua) cannot be easily distinguished from each other—both possess a single broad orange (not red) longitudinal side along each flank, and black stripes are absentNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. However, juveniles > 40 mm in length develop a “pseudo-ocellus”—a dark rounded spot near the rear lobe of the dorsal fin (Figure 8) This characteristic fades as the fish reaches adulthoodCourtenay, W.R., et al., Identity of introduced snakeheads (Pisces, Channidae) in Hawai'i and Madagascar, with comments on ecological concerns. Bishop Museum Occasional Papers, 2004. 77: p. 1–13.

]]>. Furthermore, it is noted that the young of the dwarf snakehead tend to take on their adult colouration earlier (Figure 4A)Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Figure 8: Juvenile common snakehead with pseudo-ocellus on rear of dorsal fin (circled) (Photo: Cai Yixiong, used with permission; annotation added by Kenny W.J. Chua)

Size

The common snakehead can reach a maximum size of 90 cm (standard length; see Figure 7) and weigh up to 3 kgCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Santos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>. However, lengths of around 60 cm are more commonSantos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

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Feeding

Diet
The common snakehead is a voracious predator that feeds on a variety of invertebrate and vertebrate prey. Adults feed mainly on fishes, frogs, tadpoles and crustaceansLee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>Baker, N. and K.K.P. Lim, Wild animals of Singapore. 2012, Singapore: Draco Publishing & Nature Society (Singapore). 180.

]]>Rahman, A.K.A., Freshwater Fishes of Bangladash. 1989, Department of Zoology, University of Dhaka: Zoological Society of Bangladash. 364.

]]>, while juveniles feed on fish fry, smaller crustaceans and other macroinvertebratesConlu, P.V., Guide to Philippine flora and fauna, Vol IX of Fishes. 1986: Natural Resources Management Center Ministry of Natural Resources and University of the Philippines. 495.

]]>. The larvae of this species feed on zooplanktonConlu, P.V., Guide to Philippine flora and fauna, Vol IX of Fishes. 1986: Natural Resources Management Center Ministry of Natural Resources and University of the Philippines. 495.

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Feeding behaviour
Like most other snakeheads, the common snakehead mainly hunts at night. This species is a solitary ambush predator (Video 1) that appears to be most active at duskNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. Its relatively drab colouration allows the animal to camouflage amongst aquatic vegetation and debrisNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. In addition, the common snakehead also possesses enlarged canine-like teeth which it uses to grip and tear preyNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Video 1: Captive common snakehead feeding on shrimp (Video: YouTube user 69peterek)

Air-breathing

The common snakehead is an obligate air-breather—regular trips to the surface are needed to obtain atmospheric oxygenCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>, and it can “drown” if such access is deniedLim, K.K.P., Fins and scales, in Private Lives: An Exposé of Singapore's Freshwaters, D.C.J. Yeo, L.K. Wang, and K.K.P. Lim, Editors. 2010, Raffles Museum of Biodiversity Research: Singapore. p. 136–151.

]]>. Air-breathing is enabled by a specialised cavity located above the gills. This cavity contains mucous membranes lined with a rich network of blood vessels to increase oxygen uptakeNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>, allowing the fish to tolerate poorly oxygenated waters.

Breeding

Sexing
As with other snakeheads, it is difficult to distinguish between male and female common snakeheads since their external morphologies are highly similar. However, females are on average larger than malesNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Spawning behaviour
Spawning has been reported throughout most of the year, and peaks during periods of high rainfallCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>. Spawning occurs over a shallow depression formed by removing aquatic vegetationLim, K.K.P. and P.K.L. Ng, A Guide to the Freshwater Fishes of Singapore. 1990, Singapore: Singapore Science Centre.

]]>. The fishes form a spawning embrace in which the male wraps around the female, fertilising the eggs as they are releasedNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(Video 2). The fertilised eggs then float to the surface, where they are guarded by one or both parentsCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Lee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>.The young hatch in about three daysNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Video 2: A mating pair of peacock snakeheads (Channa pulchra) exhibiting the spawning embrace typical of snakeheads (Video: YouTube user Paul Jones)

Brood care
Brood care in the common snakehead is well developed, and adults are noted to be aggressive when guarding youngNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. The young shoal near the surface (Figure 9), and are guarded by the parent(s) which remain(s) in the vicinity Courtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Lim, K.K.P. and P.K.L. Ng, A Guide to the Freshwater Fishes of Singapore. 1990, Singapore: Singapore Science Centre.

]]>(Video 3). Females become sexually mature in two years, at a length of about 30 cmChaudhry, S. Channa striata. The IUCN Red List of Threatened Species 2010: e.T166563A6237224. 2010 [cited 2015 9 September]; Available from: http://www.iucnredlist.org/details/166563/0

]]>.

g9Figure 9: A shoal of young common snakeheads near the shore of MacRitchie Reservoir, Singapore (Photo: Kenny W.J. Chua)

Video 3: A pair of giant snakeheads (Channa micropeltis) guarding their brood—the common snakehead behaves similarly (Video: YouTube user David OKY)

Human use

As food fish
The common snakehead (along with other large snakehead species) is a favoured food fish in much of Southeast Asia, including SingaporeNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>Santos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>(Figure 10). The flesh is firm, white and has minimal bones Davidson, A., Fish and fish dishes of Laos. 1975, Vientiane: Imprimerie Nationale. 202.

]]>(Figure 11). Furthermore, the flesh of the common snakehead is said to have healing properties, supposedly aiding in post-surgical recovery [seeCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Lim, K.K.P. and P.K.L. Ng, A Guide to the Freshwater Fishes of Singapore. 1990, Singapore: Singapore Science Centre.

]]>Yeo, D.C.J., K.K.P. Lim, and L.K. Wang, View from the top, in Private Lives: An Exposé of Singapore's Freshwaters, D.C.J. Yeo, L.K. Wang, and K.K.P. Lim, Editors. 2010, The Raffles Museum of Biodiversity Research: Singapore. p. 190–193.

]]>]. Given the air-breathing ability and hardiness of the common snakehead, its value as a food fish is bolstered by the ease of transporting and keeping this fish aliveNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Figure 10: Common snakeheads sold in a marketplace at Palangkaraya, Central Kalimantan (A) (Photo: Tan Heok Hui, used with permission); live common snakehead in a marketplace in Singapore; note the high density made possible by the hardiness of the fish (B) (Photo: Eric Er, used with permission)

Figure 11: Common snakehead cooked in soup (Photo: Terry Wong, used with permission)

Common snakeheads are mostly produced in monoculture systems, where they are kept at high densities in outdoor pondsWee, K.L. Snakehead (Channa striatus) farming in Thailand. FAO Corporate Document Repository 1981 [cited 2015 14 Nov]; Available from: http://www.fao.org/docrep/field/003/ac255e/ac255e00.htm

]]>. Spawning can be induced by sudden increases in water level to simulate the effects of heavy rain, or by injection of human chorionic gonadotropic hormoneYaakob, W.A.A.W. and A.B. Ali, Simple method for backyard production of snakehead (Channa striata Bloch) fry. Naga, 1992. 15(2): p. 22–23.

]]>. The fry are fed a blended mixture of trash fish and rice bran until they reach a mass of 0.7–1.0 kg in seven to ten months, upon which they are harvestedWee, K.L. Snakehead (Channa striatus) farming in Thailand. FAO Corporate Document Repository 1981 [cited 2015 14 Nov]; Available from: http://www.fao.org/docrep/field/003/ac255e/ac255e00.htm

]]>.

As sport fish
The common snakehead is occasionally fished for sport (Video 4). It is said to respond well to both baits and luresJuan Wei. Haruan - Striped Snakehead, Common Snakehead, Channa Striata. Sport Fishin.Asia 2009 [cited 2015 21 Nov]; Available from: http://sportfishin.asia/catch-reports-tips-and-techniques/snakehead-fishing/channa-striata-2/

]]>.

Video 4: Common snakehead being fished from a flooded roadside ditch. (Video: YouTube user Channa Anglers)

As aquarium pets
Given its potential size, a suitably large tank is required to maintain the common snakehead in captivity. Apart from that, common snakeheads are (with a few caveats) relatively easy to maintain in aquaria because of their air-breathing ability and tolerance for a wide range of pH valuesNg, H.H. Quick guide to snakeheads. Practical Fishkeeping 2010 [cited 2015 14 Nov]; Available from: http://www.practicalfishkeeping.co.uk/content.php?sid=3190

]]>. However, as with other large fishes, efficient filtration and regular water changes are required to minimise buildup of waste products. Since they are obligate air-breathers, one must ensure these fishes are not denied access to the water surface. However, they are powerful jumpers, hence a tight-fitting and weighted lid is necessary.

As ambush predators, common snakeheads tend to move in sudden bursts—therefore tank decor must be firmly secured to prevent them from toppling and injuring the fishes. They tend to be highly territorial and aggressive towards most fishes, so tankmates are generally not recommended. While some specimens might initially eat nothing but live food, they can be trained to take commercial pellet food, supplemented by occasional meaty treats.

As pest fish
While the common snakehead is native to Singapore, the highly predatory nature of adults of this species is a potential threat to aquaculture of other freshwater fishesNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. Furthermore, when introduced to waters outside its native distribution, the common snakehead’s high tolerance to a wide range of environmental conditions increases the chance of its establishment, thereby posing a potential risk to native aquatic faunaCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Courtenay, W.R., et al., Identity of introduced snakeheads (Pisces, Channidae) in Hawai'i and Madagascar, with comments on ecological concerns. Bishop Museum Occasional Papers, 2004. 77: p. 1–13.

]]>.

However, while widely introduced as a food fish, the common snakehead has not been listed as an invasive species under the Global Invasive Species Database unlike its congener the northern snakehead (Channa argus)Global Invasive Species Database. Channa argus. Global Invasive Species Database 2009 [cited 2015 10 Sep]; Available from: http://www.issg.org/database/species/ecology.asp?si=380&fr=1&sts=sss&lang=EN

]]>. Although established populations of the common snakehead were reported from Madagascar and Hawaii, these reports have found to be attributed to erroneous identification of the blotched snakehead (Channa maculata) Courtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>Courtenay, W.R., et al., Identity of introduced snakeheads (Pisces, Channidae) in Hawai'i and Madagascar, with comments on ecological concerns. Bishop Museum Occasional Papers, 2004. 77: p. 1–13.

]]>(Figure 12).

Figure 12: Blotched snakehead in an aquarium shop in Singapore (Photo: Kenny W.J. Chua)

Conservation status

Given its widespread distribution and tolerance, the common snakehead is listed as Least Concern on the IUCN Red ListChaudhry, S. Channa striata. The IUCN Red List of Threatened Species 2010: e.T166563A6237224. 2010 [cited 2015 9 September]; Available from: http://www.iucnredlist.org/details/166563/0

]]>. There are no known major threats to this speciesChaudhry, S. Channa striata. The IUCN Red List of Threatened Species 2010: e.T166563A6237224. 2010 [cited 2015 9 September]; Available from: http://www.iucnredlist.org/details/166563/0

]]>—exploitation of wild stocks of this species has largely stabilised, and demand is increasingly met by captive-bred fishesFAO Fisheries and Aquaculture Department. Channa striata (Bloch, 1793). Species Fact Sheets 2015 [cited 2015 20 Aug]; Available from: http://www.fao.org/fishery/species/3062/en

]]>. Furthermore, fisheries stocks in heavily fished open waters are supplemented by fishes migrating from shallow-water habitats, where they are not as heavily fishedAmilhat, E. and K. Lorenzen, Habitat use, migration pattern and population dynamics of chevron snakehead Channa striata in a rainfed rice farming landscape. Journal of Fish Biology, 2005. 67(Supplement B): p. 23–34.

]]>.

However, Channa striata is possibly a species complex (see Species complex)Courtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>. As such, re-assessment of extinction risk will be required after taxonomic revision. This is especially pertinent because the common snakehead is frequently transported for aquaculture—this could unwittingly allow as-yet unrecognised members of this species complex to hybridise, causing erosion of genetic identity.

Unlike some forest-dwelling snakehead species in SingaporeLim, K.K.P., Fishes, amphibians and reptiles, in The Singapore Red Data Book: threatened plants & animals of Singapore, G.W.H. Davison and H.C. Ho, Editors. 2008, Nature Society (Singapore): Singapore. p. 263–265.

]]>, the common snakehead is not listed on the Singapore Red Data Book, likely indicating that this highly adaptable species is not locally threatened. This is probably attributable to its general hardiness, enabling to survive in even highly modified aquatic habitats.

Taxonomy and systematics

Taxonomic hierarchy

(After Integrated Taxonomic Information SystemIntegrated Taxonomic Information System. 25Channa striata (Bloch, 1793). Integrated Taxonomic Information System 2015 [cited 2015 1 Sep]; Available from: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=166667

]]>)

Etymology
The genus name Channa is derived from the Greek word “channe”, referring to an unspecified sea perchSantos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>. The species epithet striata comes from the Latin “striatus”, referring to the dorsal stripes on this species. The common name snakehead derives from the deprecated genus name Ophicephalus (see Synonyms)—"ophis" is a Greek term referring to a snake or serpent, while "cephalus" is the Greek word for head. This name references the snake-like appearance of the fish's head due to the presence of large cephalic scales.

Synonyms
Ophicephalus striatus Bloch, 1793Bloch, M.E. and J.G. Schneider, Systema Ichthyologiae Iconibus CX illustratum. 1801, Berlin. 584.

]]>; Ophiocephalus wrahl Lacépède, 1802Lacépède, B.G., Notice historique sur la vie et les ouvrages de Dolomieu. 1802, Paris: Bossange.

]]>; Ophiocephalus chena Hamilton-Buchanan, 1822Hamilton-Buchanan, F., An Account of the Fishes Found in the River Ganges and Its Branches. 1822, Edinburgh and London.

]]>; Ophicephalus planiceps Cuvier, 1831Cuvier, G. and A. Valenciennes, Histoire Naturelles des Poissons. Vol. 7. 1831, Paris-Strasbourg. xxix+531.

]]>; Ophicephalus sowarah Bleeker, 1845; Ophiocephalus cyanospilos Bleeker, 1853; Ophiocephalus vagus Peters, 1868Peters, W.C.H., Über die von Herrn Dr F. Jagor in dem ostindischen Archipel gesammelten Fische. Monatsbericht der Akademie Wissenschaften zu Berlin, 1868. 1868: p. 254–281, 460–461.

]]>
Type specimens
No holotype was designated for Channa striata. Instead, there are two syntypes currently deposited in the Museum für Naturkunde, Berlin: ZMB 1400 and ZMB 6522 [2]. The type locality is Tranquebar, Malabar, IndiaCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>.

Description
Body largely cylindrical in cross-section but slightly compressed dorso-ventrallyNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>Santos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343]]>. Dorsal surface and flanks darker than ventral surface; dark, oblique striations present on dorsum. Large head with deeply gaping, fully toothed mouthSantos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>; caniform teeth present on lower jawNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. Cephalic shields large and distinct; sides of lower jaw parallel or convergingNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>. Pelvic fins well developed; margins of anal fin may be lined with white, but not so for caudal and dorsal fins; ocellus absentNg, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>.

Lateral line scales 53–55Santos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>. Dorsal and anal spines absent; dorsal soft rays 38–43; anal soft rays 23–27Santos, D.N. Channa striata (Bloch, 1793). Fishbase 2014 [cited 2015 9 Sep]; Available from: http://www.fishbase.org/country/CountrySpeciesSummary.php?c_code=608&id=343

]]>. Postorbital head length 28.6–37.2%; interorbital width 5.1–8.9%; preopercular length 6.2–26.4%; pelvic-anal distance 3.5–8.8%; caudal length 11.9–23.3% (measurements in percentage of standard length)Lee, P.G. and P.K.L. Ng, The systematics and ecology of snakeheads (Pisces: Channidae) in Peninsular Malaysia and Singapore. Hydrobiologia, 1994. 285: p. 59–74.

]]>.

Taxonomic history
Channa striata was originally described as Ophicephalus striatus Bloch, 1793 Bloch, M.E. and J.G. Schneider, Systema Ichthyologiae Iconibus CX illustratum. 1801, Berlin. 584.

]]>(Figure 13). The external morphology of the fish was described as follows (translated from Latin with assistance from Henrietta Woo):

“Body elongated and striped, with head tapering to a point. Lower jaw longer than upper jaw. Ventral fins small, dorsal and anal fins with brown, oblique striations. Nasal tentacles present.”

The rest of Bloch's description of the species mentions meristic characters and internal anatomy.

The genera Channa Scopoli, 1777 Scopoli, G.A., Introductio ad historiam naturalem etc. 1777, Pragae. x+506.

]]>and Ophicephalus Bloch, 1793 (sometimes misspelled as “Ophiocephalus”) were originally diagnosed by the absence or presence of pelvic fins, respectively. However, the use of this diagnostic character subsequently fell out of favourMyers, G.S. and L. Shapovalov, On the identity of Ophicephalus and Channa, two genera of labyrinth fishes. Peking Natural History Bulletin, 1931. 6: p. 33–37.

]]>, and as a result Channa and Ophicephalus were synonymised, with the senior synonym Channa taking precedence (see Ng & Lim, 1990Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>for a detailed account of the taxonomic history of the genus). Correspondingly, the species epithet was changed from the masculine striatus to the feminine striata. It was later confirmed that the loss of pelvic fins is indeed a homoplasy at the species levelLi, X., P. Musikasinthorn, and Y. Kumazawa, Molecular phylogenetic analyses of snakeheads (Perciformes: Channidae) using mitochondrial DNA sequences. Icthyological Research, 2006. 53: p. 148–159.

]]>, and thus should not be used as a character for delimiting the two genera.

Figure 13: Bloch's original description of Ophicephalus striatusBloch, M.E. and J.G. Schneider, Systema Ichthyologiae Iconibus CX illustratum. 1801, Berlin. 584.

]]>, available at the Biodiversity Heritage Library

Species complex
The wide-ranging native distribution of Channa striata suggests that it might be a species complexCourtenay, W.R. and J.D. Williams, Channa striata (Bloch, 1793): chevron snakehead, in Snakeheads (Pisces, Channidae)—A Biological Synopsis and Risk Assessment. 2004, U.S. Geological Survey Circular. p. 115–120.

]]>—i.e., Channa striata could actually comprise of multiple species. This is supported by disparities in chromosome number between specimens from India (2n = 40) Banerjee, S.K., K.K. Misra, and S.P. Ray-Chaudhuri, Chromosome numbers, genome sizes, cell volumes and evolution of snake-head family (family Channidae). Journal of Fish Biology, 1988. 33: p. 781–789.

]]>and Thailand (2n = 44)Donsakul, T. and W. Magtoon, Chromosome study on five species of channid fishes [Channa, family Channidae], from Thailand. Proceedings of the 29th Kasetsart University Annual Conference: Animal Science, Veterinary Science, and Aquaculture: Bangkok, Thailand, 1991: p. 561–574.

]]>. At the time of writing, there is no published information on chromosome number for individuals found in Singapore. Similarly, there are no published records on whether crosses between these regional varieties can produce fertile offspring. No subspecies are currently recognised from the various localities of Channa striata.

Phylogeny
The family Channidae comprises of two genera—the Eurasian Channa (ca. 26 species) and the African Parachanna (three species). It is thought that the Channoidei, which contains Channidae as the sole family, is closely related to the Percoidei and Anabantoidei. The affinity of the Channoidei to the latter group Li, X., P. Musikasinthorn, and Y. Kumazawa, Molecular phylogenetic analyses of snakeheads (Perciformes: Channidae) using mitochondrial DNA sequences. Icthyological Research, 2006. 53: p. 148–159.

]]>is especially evident from the spawning embrace behaviour exhibited by species in both groups Ng, P.K.L. and K.K.P. Lim, Snakeheads (Pisces: Channidae): natural history, biology and economic importance, in Essays in Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, L.M. Chou and P.K.L. Ng, Editors. 1990, Department of Zoology, National University of Singapore: Singapore.

]]>(see Spawning behaviour).

Molecular phylogeny of the Channidae suggests that both Channa and Parachanna are monophyletic clades Li, X., P. Musikasinthorn, and Y. Kumazawa, Molecular phylogenetic analyses of snakeheads (Perciformes: Channidae) using mitochondrial DNA sequences. Icthyological Research, 2006. 53: p. 148–159.

]]>(Figure 14). This evidence is compatible with known morphological differences in the air-breathing organs of the two genera, and thus supports their current state of classificationBonou, J.L., Révision systématique du genre Parachanna Teugels et Daget, 1984 (Pisces: Channidae). Revue d’Hydrobiolgie Tropicale, 1985. 18: p. 267–280.

]]>Senna, A., Sull’organe respiratoria soprobranchiale degli Afiocefalidi e sus semplificazione in Parophiocephalus subg. N. Monitore Zoologico Italiano, 1924. 35: p. 149–160.

]]>. Within the genus Channa are several monophyletic clades. Channa striata is sister to the clade containing the “dwarf snakeheads” Channa bleheri, Channa gachua, Channa orientalis, and few larger species (clade B; Figure 14). Together, they possibly diverged from the clade containing Channa argus, Channa asiatica and Channa maculata (clade 4; Figure 14). However, the exact relationship between Channa striata, clade B, clade 3 and clade 4 remains uncertain because of poor support values for the phylogenetic tree (Figure 14).

Figure 14: Maximum-likelihood tree for the Channidae reconstructed using the ND2 gene and flanking sequences as characters. Numbers above and below branches represent Bayesian posterior probability values and bootstrap probabilities obtained from 500 replications of maximum-parsimony analysis, respectively. Bold lines correspond to indicated characters, i.e., gular scales and scale(s) on lower jaw. (Reproduced from Li et al., 2006Li, X., P. Musikasinthorn, and Y. Kumazawa, Molecular phylogenetic analyses of snakeheads (Perciformes: Channidae) using mitochondrial DNA sequences. Icthyological Research, 2006. 53: p. 148–159.

]]>; emphasis on Channa striata added; used with permission from corresponding author, pending permission from publisher)

Useful links

Snakehead species in Singapore [link]
More on the common snakehead in Singapore [link]
Maintaining snakeheads in captivity [link]
Common snakeheads as sport fish [link]
Recipe for snakehead soup [link]

References

Texts

Multimedia
Figures 1, 5 & 10. Photographs by Eric Er.
Figures 2, 3, 4, 6, 7, 9 & 12. Map, photographs and illustrations by Kenny W.J. Chua.
Figures 4, 5 & 10. Photographs by Tan Heok Hui.
Figure 8. Photograph by Cai Yixiong.
Figure 11. Photograph by Terry Wong.
Figure 13. Scan of manuscriptBloch, M.E. and J.G. Schneider, Systema Ichthyologiae Iconibus CX illustratum. 1801, Berlin. 584.

]]>  by the Biodiversity Heritage Library.
Figure 14. Figure by Li et al. (2006)Donsakul, T. and W. Magtoon, Chromosome study on five species of channid fishes [Channa, family Channidae], from Thailand. Proceedings of the 29th Kasetsart University Annual Conference: Animal Science, Veterinary Science, and Aquaculture: Bangkok, Thailand, 1991: p. 561–574.

]]>.
Video 1. "Channa striata vs shrimp HD" by 69peterek YouTube Channel, 2 Jul 2013. URL: https://www.youtube.com/watch?v=m_2lv9rZUCs [cited 21 Nov 2015]
Video 2. "Snakeheads Spawning Ritual - Eggs Released" by Paul Jones YouTube Channel, 21 Oct 2012. URL: https://www.youtube.com/watch?v=JxZqQxhTV5A [cited 2015 1 Nov].
Video 3. "Beautiful leisurely Giant snakehead fish and fry" by David OKY YouTube Channel, 19 May 2014. URL: https://www.youtube.com/watch?v=LnNHozXqnyM [cited 2015 1 Nov].
Video 4. "Channa Anglers Common Snakehead Haruan Gabus Fishing Channa Striata" by Channa Anglers YouTube Channel, 24 Aug 2014. URL: https://www.youtube.com/watch?v=4WBcB5ilGes [cited 21 Nov 2015]

See linked documents to understand how this page was conceptualised, and the methods used in compiling the relevant information.
Last updated by Kenny W.J. Chua (kenny.chua[at]u.nus.edu) on 21 Nov 2015.

This page was authored by Kenny Chua Wei Jie

Last curated on 21 Nov 2015