The walking catfish is found in the muddy substrates of several water systems. This species can be found in freshwater, brackish water, and terrestrial environments. It is common in lowland bodies of water such as irrigation channels, lakes, rice fields, and wetlands. It has been recorded at a depth of one meter but the species’ maximum depth is unknown. (Allen, 2013; Froese and Luna, 2015)burrows into the mud during cold and dry months to survive poor weather conditions. It predominately inhabits tropical waters at a temperature of 18 degrees Celsius or above, but tolerates terrestrial habitats with temperatures between 0-18 degrees Celsius. While this species is found in a multitude of water conditions, it is abundant in swampy waters. can survive outside of the water and travel on land as long as its gills stay moist. It is most common to see outside of the water after heavy rains.
Clarias have been known to have venomous spines located in front of their dorsal fins that can sting predators. (Allen, 2013; Das, 2002; Froese and Luna, 2015; Ng and Kottelat, 2008; Page and Burr, 1998)has an elongated body with a narrow head and irregular bumps on its spine. The walking catfish is characterized by having 54–60 vertebrae, 63–74 dorsal-fin rays, and 47–58 anal-fin rays. It also has a long and thin cavity between the frontal and parietal, or side bones, in the skull. In the wild, the walking catfish is brown with a white underside; however other colorations, such as albino, mottled, and piebald can be found in cultivated individuals. The female walking catfish lays bright orange eggs. fingerlings lack pigment and appear translucent. As they develop, they become brown or a dark green-black. The walking catfish can grow to be 8 to 47cm long and weigh up to 1.2kg. Males and females are similar in size and shape, but there are some defining characteristics. A female has a broader belly than a male that is especially prominent during mating season. A male can also be distinguished by the presence of dorsal fin spots. Species of
The walking catfish eggs are adhesive in nature and are sensitive to environmental disturbances. Fertilized eggs have very poor survival rates due to this sensitivity and in result, do not yield many fry. Thakur reports that the walking catfish had an average fertilization rate of 68.5 percent, an average hatching percent of 36.5, and an average survival rate of 10.5 percent (1976). The incubation period generally lasts 18-24 hours. Embryos begin to display twitching inside the egg after 12-18 hours and usually hatch in 20-24 hours. Typically, larvae weigh approximately 0.00186g upon hatching. Sex is differentiated physically: male walking catfish have a pointed genital region, while female walking catfish have a thick and rounded genital region. Larval development is very rapid and the larvae are able to swim strongly within 3 days. After 20-30 days following hatching, the walking catfish larvae become fingerlings. The catfish fingerling is an intermediate stage between a larva and an adult. An adult walking catfish has indeterminate growth and males and females are roughly the same size. (Argungu, et al., 2013; Chinabut, et al., 1991; Mookerjee and Mazumdar, 1950; Thakur, 1976; Verreth, et al., 1993)
The walking catfish mate seasonally in the summer during the months between June and August. Heavy rains have a signaling effect on the catfish and are usually a prerequisite for mating. However, it has been found that the walking catfish, unlike other members of the Clariidae family have the ability to breed in stagnant water. A male and female walking catfish will start swimming together a couple days prior to mating. The pair will look for a cave or terrestrial substrate to lay their eggs. Once a place is found, the male and female will both take part in digging a hole in that area. The female walking catfish will initiate mating by nudging the male's genital area with her snout until he engages. Once the male is engaged, the female, despite having initiated the mating, has to be courted into breeding. The male will make body contact with the female and repeat the same nudging behavior. The male walking catfish will make several circling movements around the female. The male will continue to circle the female pulling her closer and closer until he loops his body around hers in a spawning embrace. The walking catfish spawns in cycles and the first rounds of spawning produce none or few eggs, usually less than five. Later spawnings, with the same mate, produce more eggs and the mating ritual becomes minimal or is absent entirely. Each spawning lasts for around ten seconds. The female will then separate herself from the loop and swim away, only to return shortly thereafter to begin another spawning cycle. The entire spawning process can take up to 20 hours. On average, an adult female lays around 7,000-9,000 eggs. The walking catfish is monogamous during the mating season and has multiple spawning cycles with the same mate. (Areerat, 1987; Cheah, et al., 1990; Das, 2002; Froese and Luna, 2015; Thakur, 1976)
Walking catfish are sexually mature at age one. The breeding season for walking catfish is between the months of June-August. These catfish breed with a single mate during the season via multiple spawning cycles in which increasingly more eggs are produced. The eggs are internally fertilized during the spawning embrace and an adult female will produce an average of 7,000-9,000 eggs a season. The walking catfish fry become independent after three days. (Argungu, et al., 2013; Cheah, et al., 1990; Das, 2002; Thakur, 1976)
The male guards the nest from predators, such as the clown loach (Chromobotia macracanthus) and yoyo loach (Botia lohachata), immediately following spawning. The female will return once the eggs have hatched and the male and female take part in protecting the fry until they are independent. The parental investment only extends to 24 hours following the hatching. By the third day, the fry are capable of swimming strongly and they are no longer guarded by the parents. (Areerat, 1987; Cheah, et al., 1990; Das, 2002; Hossain, et al., 2006; Thakur, 1976)
The lifespan of the walking catfish has not been reported. However, a close relative of the walking catfish, the African catfish (Clarias camerunensis) has an expected lifespan of 16.2 years in captivity. It is likely that the walking catfish has a similar longevity. (Carey and Judge, 2000)
The home range of an individual of this species is unknown.
Fish have a lateral line that they use to sense vibrations in the water and perceive their surroundings. Additionally, several species of catfish within the Clariidae family communicate using sounds produced by their pectoral spine. However, it is unknown whether the walking catfish communicates this way. (Bleckmann and Zelick, 2009)
Species of otters are major predators of the walking catfish. Other predators include large reptiles (crocodiles), birds - namely fish eagles (Haliaeetus)- and mammals, including humans (Homo sapiens). has several anti-predator adaptations. The most prevalent coloration is brown with white on its ventral side. This color pattern enables the walking catfish to blend in with its muddy habitat and hide from predators. The sheer size of the walking catfish provides some protection against predation. Additionally, Clarias species have a venomous sting and sharp dagger-like structures located in front of their dorsal fins. (Page and Burr, 1998)
The walking catfish is host to a variety of helminth parasites that include tapeworms (Cestoda, Lytocestus indicus),and trematodes, (Opegaster, Orientocreadium, Euclinostomum, and Caryophyllaeus indicus). Opegaster is the most prevalent trematode parasite in the walking catfish and it predominately inhabits the gut and gall bladder. Cauyan et al. (2013) found that the gut and gall bladder of a walking catfish was infected with a mean intensity of 20 individuals in Opegaster. also had a mean intensity of approximately 8 individuals Opegaster in the spleen and liver. The mean intensity was calculated by dividing the number of parasites by the number of infected fish. The walking catfish has a predatory role in the marine food web and preys on the organisms listed in the food habits section. It also provides nutrients to the marine ecosystem through the excretion of nutrients. (Ash, et al., 2011; Cauyan, et al., 2013; Moghe, 1925)
The walking catfish poses a threat as an invasive species. ("Wild animal importing, exporting, selling, and possession regulations", 2001), once introduced, is hard to contain and control due to its mass spawning that produces several thousands of eggs, its voracious diet, and ability to survive in muddy and low-oxygenated conditions. Its opportunistic feeding habits may threaten some sport fish in Florida. Costly containment methods, such as the use of barrier fences, have been utilized to prevent walking catfish from invading fish stocks.
The walking catfish is listed as a species of "Least Concern" on the IUCN Red List, and has no special status on the US Federal List or by CITES.
Argungu et al. notes that the walking catfish is threatened and is becoming critically endangered in its native range in Asia (2013). Periods of drought and human disruption of the walking catfish's natural habitat has contributed to its decline in Malaysia and India. The introduction of the larger African catfish (Clarias gariepinus) has out competed the walking catfish and reduced the population of . Currently, induced spawning and artificial breeding have been used as means of conservation for the walking catfish in their native range.
There are some forms of anti-conservation in place in the United States to prevent the spread of the species. Ohio has prohibited the possession of the walking catfish and Maryland, Idaho, Rhode Island have placed restrictions on the import, sale, and possession of the walking catfish. Eradication via poison is not an option because no known toxicants are species-specific. More effort has been placed on containment but this has been a difficult task because the walking catfish can move on land. ("Wild animal importing, exporting, selling, and possession regulations", 2001; Argungu, et al., 2013; Froese and Luna, 2015; Hossain, et al., 2006)
Sarah Rainey (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
areas with salty water, usually in coastal marshes and estuaries.
an animal that mainly eats meat
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
an animal that mainly eats decomposed plants and/or animals
particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
parental care is carried out by females
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
mainly lives in water that is not salty.
An animal that eats mainly plants or parts of plants.
Animals with indeterminate growth continue to grow throughout their lives.
An animal that eats mainly insects or spiders.
fertilization takes place within the female's body
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
makes seasonal movements between breeding and wintering grounds
eats mollusks, members of Phylum Mollusca
Having one mate at a time.
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)
an animal that mainly eats fish
an animal that mainly eats plankton
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
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