Walking catfish
Encyclopedia
The walking catfish, Clarias batrachus, is a species of freshwater
airbreathing catfish
found primarily in Southeast Asia
, so named for its ability to "walk
" across dry land, to find food or suitable environments. While it does not truly walk as most biped
s or quadruped
s do, it has the ability to use its pectoral fins to keep it upright as it makes a sort of wiggling motion with snakelike movements. It can survive using this form of locomotion
as long as it stays moist. This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams and rivers (Mekong
and Chao Phraya basins), flooded rice paddies or temporary pools which may dry up. When this happens, its "walking" skill allows the fish to move to other sources of water.
and anal fins as well as several pairs of sensory barbels
. The skin is scaleless but covered with mucus
, which protects the fish when it is out of water.
One main distinction between the walking catfish and native North America
n Ictalurid catfish is the walking catfish's lack of an adipose fin.
This fish needs to be handled carefully when fishing it out due to its hidden embedded sting or thorn-like defensive mechanism hidden behind its fins (including the middle ones before the tail fin, just like the majority of all catfish).
, eastern India
, Sri Lanka
, Bangladesh
, Burma, Indonesia
, Singapore
and Brunei
. It is also located in the Philippines
and is called hito or simply "catfish" by the locals. During its season in the Philippines
, it is widely distributed throughout the country and many consumers buy this product alive. This catfish is a tropical species and prefers a water temperature in the range of 10–28 °C (50–82.4 F).
Walking catfish thrive in stagnant, frequently hypoxic
waters, and are often found in muddy pond
s, canal
s, ditch
es and similar habitats. The species spends most of its time on, or right above, the bottom surface
, with occasional trips to the surface to gulp air.
; it feeds on smaller fish
, molluscs and other invertebrates as well as detritus
and aquatic weeds. It is a voracious eater which consumes food rapidly and this habit makes it a particularly harmful invasive species.
it is an invasive species
, which is now established in Florida
and reported in California
, Connecticut
, Georgia
, Massachusetts
, and Nevada
.
The walking catfish was imported to Florida, reportedly from Thailand
, in the early 1960s for the aquarium trade. The first introductions apparently occurred in the mid-1960s when adult fish
imported as brood stock escaped, either from a fish farm in northeastern Broward County or from a truck transporting brood fish between Dade and Broward counties. Additional introductions in Florida, supposedly purposeful releases, were made by fish farmers in the Tampa Bay
area, Hillsborough County
in late 1967 or early 1968, after the state banned the importation and possession of walking catfish. Aquarium releases likely are responsible for introductions in other states. Dill and Cordone (1997) reported that this species has been sold by tropical fish dealers in California for some time. They have also been spotted occasionally in the Midwest.
In Florida, walking catfish are known to have invaded aquaculture farms, entering ponds where these predators prey on fish stocks. In response, fish farmers have had to erect fences to protect ponds. Authorities have also created laws that ban possession of walking catfish.
this fish is known as Pla Duk Dan . It is a common inexpensive food item, prepared in a variety of ways, being often offered by street vendors, especially barbecue
d or fried.
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
airbreathing catfish
Airbreathing catfish
Airbreathing catfishes are fishes comprising the family Clariidae of order Siluriformes. There are about 14 genera and 100 species of clariids...
found primarily in Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, so named for its ability to "walk
WALK
WALK may refer to:*WALK , a radio station licensed to East Patchogue, New York, United States*WALK-FM, a radio station licensed to Patchogue, New York, United States...
" across dry land, to find food or suitable environments. While it does not truly walk as most biped
Biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...
s or quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
s do, it has the ability to use its pectoral fins to keep it upright as it makes a sort of wiggling motion with snakelike movements. It can survive using this form of locomotion
Animal locomotion
Animal locomotion, which is the act of self-propulsion by an animal, has many manifestations, including running, swimming, jumping and flying. Animals move for a variety of reasons, such as to find food, a mate, or a suitable microhabitat, and to escape predators...
as long as it stays moist. This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams and rivers (Mekong
Mekong
The Mekong is a river that runs through China, Burma, Laos, Thailand, Cambodia and Vietnam. It is the world's 10th-longest river and the 7th-longest in Asia. Its estimated length is , and it drains an area of , discharging of water annually....
and Chao Phraya basins), flooded rice paddies or temporary pools which may dry up. When this happens, its "walking" skill allows the fish to move to other sources of water.
Characteristics and anatomy
Walking catfish are around 30 cm (a foot or so) in length and have an elongated body shape. Often covered laterally in small white spots, the body is mainly colored a gray or grayish brown. This catfish has long-based dorsalDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and anal fins as well as several pairs of sensory barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
. The skin is scaleless but covered with mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
, which protects the fish when it is out of water.
One main distinction between the walking catfish and native North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n Ictalurid catfish is the walking catfish's lack of an adipose fin.
This fish needs to be handled carefully when fishing it out due to its hidden embedded sting or thorn-like defensive mechanism hidden behind its fins (including the middle ones before the tail fin, just like the majority of all catfish).
Location and habitat
The walking catfish is a native of South East Asia including Malaysia, ThailandThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, eastern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
, Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
, Burma, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
and Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
. It is also located in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
and is called hito or simply "catfish" by the locals. During its season in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, it is widely distributed throughout the country and many consumers buy this product alive. This catfish is a tropical species and prefers a water temperature in the range of 10–28 °C (50–82.4 F).
Walking catfish thrive in stagnant, frequently hypoxic
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
waters, and are often found in muddy pond
Pond
A pond is a body of standing water, either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens, water features and koi ponds; all designed for aesthetic ornamentation as landscape or architectural...
s, canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
s, ditch
Ditch
A ditch is usually defined as a small to moderate depression created to channel water.In Anglo-Saxon, the word dïc already existed and was pronounced 'deek' in northern England and 'deetch' in the south. The origins of the word lie in digging a trench and forming the upcast soil into a bank...
es and similar habitats. The species spends most of its time on, or right above, the bottom surface
Substrate (aquarium)
The substrate of an aquarium refers to the material used on the tank bottom. It can affect water chemistry, filtration, and the well-being of the aquarium's inhabitants, and is also an important part of the aquarium's aesthetic appeal...
, with occasional trips to the surface to gulp air.
Diet and eating habits
In the wild, the natural diet of this creature is omnivorousOmnivore
Omnivores are species that eat both plants and animals as their primary food source...
; it feeds on smaller fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, molluscs and other invertebrates as well as detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
and aquatic weeds. It is a voracious eater which consumes food rapidly and this habit makes it a particularly harmful invasive species.
As invasive species
In the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
it is an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
, which is now established in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and reported in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Connecticut
Connecticut
Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...
, Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, and Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
.
The walking catfish was imported to Florida, reportedly from Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, in the early 1960s for the aquarium trade. The first introductions apparently occurred in the mid-1960s when adult fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
imported as brood stock escaped, either from a fish farm in northeastern Broward County or from a truck transporting brood fish between Dade and Broward counties. Additional introductions in Florida, supposedly purposeful releases, were made by fish farmers in the Tampa Bay
Tampa Bay
Tampa Bay is a large natural harbor and estuary along the Gulf of Mexico on the west central coast of Florida, comprising Hillsborough Bay, Old Tampa Bay, Middle Tampa Bay, and Lower Tampa Bay."Tampa Bay" is not the name of any municipality...
area, Hillsborough County
Hillsborough County, Florida
As of the census of 2000, there were 998,948 people, 391,357 households, and 255,164 families residing in the county. The population density was 951 people per square mile . There were 425,962 housing units at an average density of 405 per square mile...
in late 1967 or early 1968, after the state banned the importation and possession of walking catfish. Aquarium releases likely are responsible for introductions in other states. Dill and Cordone (1997) reported that this species has been sold by tropical fish dealers in California for some time. They have also been spotted occasionally in the Midwest.
In Florida, walking catfish are known to have invaded aquaculture farms, entering ponds where these predators prey on fish stocks. In response, fish farmers have had to erect fences to protect ponds. Authorities have also created laws that ban possession of walking catfish.
As food
In ThailandThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
this fish is known as Pla Duk Dan . It is a common inexpensive food item, prepared in a variety of ways, being often offered by street vendors, especially barbecue
Barbecue
Barbecue or barbeque , used chiefly in the United States, Canada, the United Kingdom, New Zealand and Australia is a method and apparatus for cooking meat, poultry and occasionally fish with the heat and hot smoke of a fire, smoking wood, or hot coals of...
d or fried.
Aquarium
A white variation with black patterns are commonly seen in aquarium fish trade. However this color variation is also prohibited where walking catfish are banned. Very well rooted plants and large structures that provide some shade should be included. Any tankmates small enough will be eaten.See also
- Eel catfishEel catfishThe eel catfish, Channallabes apus, is an airbreathing catfish found in the muddy swamps of the tropics of western Africa. The fish is 30 - 40 cm long and is notable for the ability to propel itself out of the water to catch prey. This species was formerly thought to be the sole member of its genus...
- List of freshwater aquarium fish species
- List of invasive species in the Everglades
External links
- Ros, Wolfgang (2004): "Clarias batrachus - Erfolgreiche Froschwels-Nachzucht im Aquarium", Datz 57 (7): 12-15.
- Ros, Wolfgang (2006): "Clarias batrachus - Auslösen der Fortpflanzung bei Froschwelsen", Datz 59 (4): 33-37.