Clarias batrachus (walking catfish)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- History of Introduction and Spread
- Habitat List
- Natural Food Sources
- Water Tolerances
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Environmental Impact
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Links to Websites
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Clarias batrachus (Linnaeus, 1758)
Preferred Common Name
- walking catfish
Other Scientific Names
- Clarias assamensis Day, 1877
- Clarias jagur Hamilton, 1822
- Clarias magur Hamilton, 1822
- Clarias punctatus Valenciennes, 1840
- Macropteronotus jagur Hamilton, 1822
- Macropteronotus magur Hamilton, 1822
- Silurus batrachus Linnaeus, 1758
International Common Names
- English: albino walking fish; catfish, walking; clarias catfish; climbing perch; freshwater catfish; magur; Philippine catfish; thai hito; thailand catfish; toyman's spotted catfish
- Russian: klarievyi som
Local Common Names
- Bangladesh: koi; magur
- Cambodia: trey andaing roueng; trey andeng; trey andèng
- Denmark: vandremalle
- Finland: konnamonni
- Germany: froschwels; waanderwels; Wanderwels
- India: khamagur; kug-aa; kug-ga; magur; mahgur; mah-gur; mangri; marpoo; masarai; ngakra; yerivahlay
- Indonesia: cá trèn tráng; ikan keeling; ikan keling; ikan lele; leleh
- Laos: pa douk; pla douk
- Malaysia: ikan lele; keli
- Myanmar: nga-khoo
- Nepal: mungri
- Philippines: alimudan; hito; hitong batukan; ito; kawatsi; paltat; pantat; Thai hito
- Sweden: ålmal
- Thailand: pla duk; pla duk dam; pla duk dan; pla duk nam jued; pla duk nam juend; plad duk dan
- Vietnam: cá trê tráng; cá trèn trang
Summary of InvasivenessTop of page
Originating in South-East Asia, C. batrachus, the walking catfish, has been introduced throughout the world for the purposes of aquaculture and as an ornamental aquarium fish. Its ability to ‘walk’ over land aided by its pectoral fins, combined with high fecundity and voracious feeding habits have led to this species becoming both a threat to native fish species and an invader of fish farms.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Actinopterygii
- Order: Siluriformes
- Family: Clariidae
- Genus: Clarias
- Species: Clarias batrachus
DescriptionTop of page
C. batrachus has an elongated body, broad at the anterior and narrow at the posterior. C. batrachus is similar in size and appearance to C. macrocephalus but can be distinguished from the latter species by the shape of the occipital process in the head portion. The occipital process is round-shaped in C. macrocephalus but pointed in C. batrachus. Unlike C. macrocephalus, C. batrachus does not have large numbers of small white spots along the sides of its body (Teugels et al., 1999). C. batrachus lacks an adipose fin. Dorsal and anal fins are without spines, pectoral fins are strong with fine serrations on both edges, pelvic fins are small and the caudal fin is not confluent with dorsal or anal fin. The mouth is wide and has four pairs of well-developed barbels, with the maxillary barbels reaching to the middle or base of the pectoral fin (Talwar and Jhingran, 1991).
The body of the normal coloured variety is greyish to olive in colour with a whitish underside. Other varieties include albino with a white body and reddish eyes, and a pink variety with normal coloured eyes (Axelrod et al., 1971). Various multi-coloured varieties are becoming more common in the tropical fish aquarium trade.
DistributionTop of page
C. batrachus is indigenous to the inland waters of South-East Asia in the Mekong and Chao Phraya basins, the Malaysian Peninsula, Sumatra, Java and Borneo. It also inhabits the inland waters of South Asian countries such as Sri Lanka, India, Bangladesh, Pakistan, Nepal, Laos, Vietnam, Singapore, Thailand, Cambodia and Brunei Darussalam. This species can be cultivated in areas with a tropical climate. Like the African catfish, C. gariepinus, it is a hardy fish that can be densely stocked in low oxygen waters making it ideal for culture in areas with a limited water supply. Unlike C. gariepinus, C. batrachus is not widely cultivated outside of its natural range, probably due to its slower growth rates compared to the African species. C. batrachus has been introduced into countries such as Guam, Philippines, China, Taiwan, the UK, the USA (Florida) and Papua New Guinea either for the aquaculture or for the ornamental fish trade.
Within the United States, Nico (2007, and references within) lists non-indigenous occurrences of C. batrachus in California, Connecticut, Florida, Georgia, Massachusetts and Nevada.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Pacific, Western Central||Present||Native||Froese and Pauly, 2004|
|Bangladesh||Present||Native||Rahman , 1989; Froese and Pauly, 2004|
|Cambodia||Present||Native||Kottelat , 1998; Froese and Pauly, 2004|
|China||Present||Introduced||Welcomme, 1988; Froese and Pauly, 2004|
|-Hong Kong||Present||Introduced||Not invasive||Welcomme, 1988|
|India||Present||Native||Froese and Pauly, 2004|
|-Uttar Pradesh||Present||CAB ABSTRACTS Data Mining 2001|
|Indonesia||Present||Native||Allen , 1991; Froese and Pauly, 2004|
|Japan||Present||Introduced||Froese and Pauly, 2009|
|Laos||Present||Native||Kottelat , 1998; Froese and Pauly, 2004|
|Malaysia||Present||Native||Kottelat , 1998; Froese and Pauly, 2004|
|Myanmar||Present||Native||Froese and Pauly, 2004|
|Nepal||Present||Native||Shrestha , 1994; Froese and Pauly, 2004|
|Pakistan||Present||Native||Kottelat , 1985; Froese and Pauly, 2004|
|Philippines||Present||Introduced||Welcomme, 1988; Froese and Pauly, 2004|
|Singapore||Present||Native||Menon , 1999; Froese and Pauly, 2004|
|Sri Lanka||Present||Native||Pethiyagoda , 1991; Froese and Pauly, 2004|
|Taiwan||Present||Introduced||Welcomme, 1988; Froese and Pauly, 2004|
|Thailand||Present||Native||Vidthayanon and et al. , 1997; Froese and Pauly, 2004|
|Vietnam||Present||Native||Kottelat , 1998; Froese and Pauly, 2004|
|USA||Present||Introduced||Froese and Pauly, 2004|
|-Florida||Present||Introduced||Invasive||Courtenay and et al. , 1974; Welcomme, 1988; Nico, 2007|
|-Georgia||Present, few occurrences||Introduced||Nico, 2007|
|-Massachusetts||Present, few occurrences||Introduced||Nico, 2007|
|-Nevada||Present, few occurrences||Introduced||Nico, 2007|
|UK||Present||Introduced||Not invasive||Welcomme, 1988|
|Guam||Present||Introduced||Welcomme, 1988; Froese and Pauly, 2004|
|Papua New Guinea||Present||Introduced||Allen , 1991; Froese and Pauly, 2004|
History of Introduction and SpreadTop of page
C. batrachus was imported into Florida for the aquarium trade in the 1960s and it is suggested they were purposefully released by fish farmers in the late 1960s (Nico, 2007, and references within).
IntroductionsTop of page
|Introduced to||Introduced from||Year||Reason||Introduced by||Established in wild through||References||Notes|
|Natural reproduction||Continuous restocking|
|China||Thailand||1978||Aquaculture (pathway cause)||Private sector||FAO (1997)|
|Guam||Aquaculture (pathway cause)||Unknown||Yes||Welcomme (1988)|
|Hong Kong||Thailand||1970||Aquaculture (pathway cause)||Unknown||Welcomme (1988)|
|Japan||Yes||Froese and Pauly (2007)|
|Papua New Guinea||Unknown||Yes||Welcomme (1988)|
|Philippines||Thailand||1972||Aquaculture (pathway cause)||Unknown||Yes||Juliano and et al. (1989); Juliano et al. (1989)|
|Sulawesi||Java||1939||Aquaculture (pathway cause)||Yes||FAO (1997)|
|Taiwan||Thailand||1972||Aquaculture (pathway cause)||Unknown||Yes||Welcomme (1988)|
|UK||South East Asia||Ornamental purposes (pathway cause)||Unknown||Welcomme (1988)|
|USA||Thailand||1960-1969||Ornamental purposes (pathway cause)||Unknown||Yes||FAO (1997)|
HabitatTop of page
C. batrachus inhabits lowland streams, swamps, ponds ditches, rice paddies, rivers, flooded areas, canals and stagnant water (Froese and Pauly, 2009).
Habitat ListTop of page
|Estuaries||Present, no further details|
|Irrigation channels||Present, no further details|
|Lakes||Present, no further details|
|Pig farms||Present, no further details|
|Poultry farms||Present, no further details|
|Ricefields||Present, no further details|
|Rural areas||Present, no further details|
|Urban / peri-urban areas||Present, no further details|
|Floodplains||Present, no further details|
|Wetlands||Present, no further details|
Natural Food SourcesTop of page
|Food Source||Life Stage||Contribution to Total Food Intake (%)||Details|
|insect eggs and pupae||Adult/Broodstock/Fry/Larval|
ClimateTop of page
|A - Tropical/Megathermal climate||Preferred||Average temp. of coolest month > 18°C, > 1500mm precipitation annually|
|C - Temperate/Mesothermal climate||Tolerated||Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C|
Water TolerancesTop of page
|Parameter||Minimum Value||Maximum Value||Typical Value||Status||Life Stage||Notes|
|Ammonia [unionised] (mg/l)||3.42||Harmful||Fry||LC 50 value|
|Ammonium [ionised] (mg/l)||15.78||Harmful||Fry||LC 50 value|
|Nitrite (mg/l)||35.60||Harmful||Fry||LC 50 value|
|Water pH (pH)||6-9||Optimum||Adult|
|Water pH (pH)||>1||<3||Harmful||Adult|
|Water temperature (ºC temperature)||<9.8||Harmful||Adult|
|Water temperature (ºC temperature)||25||Optimum||Adult|
Means of Movement and DispersalTop of page
Natural Dispersal (Non-Biotic)
Dispersal has occurred via networks of canals and also by overland migration on rainy nights (Nico, 2007).
Pathway CausesTop of page
Pathway VectorsTop of page
Impact SummaryTop of page
|Fisheries / aquaculture||Positive|
Environmental ImpactTop of page
C. batrachus was introduced into Florida, USA from Thailand and was accidentally released into the aquatic environment from the Penagra Aquariums, west of Deerfield Beach in Broward county, during the mid 1960s (Courtenay et al., 1974). In the 1970s, this exotic catfish species expanded to more than 25% of the freshwater area of Florida (Courtenay, 1978) and is considered as one of the most invasive and harmful non-indigenous species in the Gulf of Mexico ecosystem. The rapid spread of C. batrachus throughout Florida is a potential threat to native fish species due to its voracious and opportunistic feeding habits, high fecundity and its ability to migrate on land. Courtenay and Miley (1975) reported that in small wetland pools during the dry season, C. batrachus can quickly become the dominant species due to its air-breathing abilities.
In the Philippines, the exotic C. batrachus has displaced many of the native catfish species including the indigenous Clarias macrocephalus in irrigation canals, lakes and rivers (Juliano et al., 1989). In Taiwan, the faster growth of the introduced C. batrachus has led to the diminished importance of the local Clarias fuscus as a cultured species (Liao and Lia, 1989). In both these countries, despite the obvious economic benefits from aquaculture of an introduced species, the demand for the local indigenous catfish species is still higher and commands a better market value.
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Highly mobile locally
Uses ListTop of page
- Aquaria fish
- Pet/aquarium trade
Human food and beverage
- Cured meat
- Fresh meat
- Frozen meat
- Live product for human consumption
- Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)
Similarities to Other Species/ConditionsTop of page
C. gariepinus x C. batrachus
Prevention and ControlTop of page
Florida state banned the importation and possession of catfish in the late 1960s (Courtney and Stauffer, 1990 in Nico, 2007).
In Florida, fish farmers have erected protective fences around their ponds to prevent the entry of Clarias batrachus which prey on their fish stocks (Courtney and Stauffer, 1990 in Nico, 2007).
ReferencesTop of page
Ali AB, 1989. Some ecological aspects of fish population in tropical rice fields. Hydrobiologia, 190:215-222.
Allen GR, 1991. Field guide to the freshwater fishes of New Guinea. Madang, Papua New Guinea: Christensen Research Institute, 180 pp.
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Chanratchakool P, 2000. Use of sodium chloride to reduce mortality of walking catfish fry (Clarias batrachus Linn.) from transportation. MSc Thesis. Bangkok, Thailand: Faculty of Fisheries, Kasetsart University, 15-16.
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ContributorsTop of page
20/01/2010 Updated by:
Vicki Bonham, CABI, Nosworthy Way, Wallingford, OX10 8DE, UK
Fish Nutrition Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
Distribution MapsTop of page
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