Catfish (order Siluriformes) are a diverse group of fish. Named for their prominent barbels, which give the image of cat-like whiskers, they are found primarily in freshwater environments of all kinds, with species on every continent except Antarctica. Some species from the families Ariidae and Plotosidae are also found in marine environments. They feature some of the smallest known vertebrates, including the candiru, the only vertebrate parasite to attack humans, as well as Pangasianodon gigas, the largest reported freshwater fish. There are armour-plated types and also naked types, but they do not have scales. Not all catfish families have prominent barbels; what defines a fish as being in the order Siluriformes are certain features of the skull and swimbladder.
Catfish have no scales. All catfish, except members of Malapteruridae (electric catfish), possess a strong, hollow, bonified leading ray on their dorsal and pectoral fins, through which a stinging protein can be delivered if the fish is irritated. In members of the family Plotosidae, and of the genus Heteropneustes, this protein is so strong it may hospitalize humans unfortunate enough to receive a sting.
Catfish, which have a sweet, mild flesh, are important as food fish throughout the world. Ictalurids are cultivated in North America (especially in the Deep South, with Mississippi being the largest domestic catfish producer) while Clariids and Pangasiids are heavily cultured in Africa and Asia. Farmed Pangasius can sometimes be found in US supermarkets. However, the fish must be labeled as "Basa fish" (instead of catfish) due to measures intended to protect the American catfish farming industry.
Representatives of the genus Ictalurus have been misguidedly introduced into European waters in the hope of obtaining a sporting and a food resource. However, the European stock of American catfishes has not achieved the dimensions of these fishes in their native waters, and have only increased the ecological pressure on native European fauna. Clarias spp. have also been introduced in the freshwaters of Florida, with the voracious catfish becoming a major alien pest there.
Catfish range in size and behavior from the heaviest, the giant Mekong catfish in Southeast Asia and the longest, the wels catfish of Eurasia, to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa.
The wels catfish, Silurus glanis, is the only native catfish species of Europe, besides the much smaller related Aristotle catfish found in Greece. Mythology and literature record wels catfish of astounding proportions, yet to be scientifically proved. The average size of the species is about 1.2 m to 1.6 m, and fish more than 2 m are very rare. The largest specimens on record measure more than 2.5 m in length and sometimes exeeded 100 kg. The wels catfish was introduced to Britain, Italy, Spain, Greece and some other countries during the last century. The species has flourished in the warm lakes and rivers of Southern Europe. The River Danube, River Po in Italy and the River Ebro in Spain are famous for huge wels catfish, which grow up to 2 m. These habitats contain plenty of food and lack natural predators.
A very large wels catfish was caught by Kevin Maddocks on August 6, 1999, recorded at 91.62 kg (202 lb). Tim Pruitt of Illinois caught the largest blue catfish, Ictalurus furcatus, in the Mississippi River on May 22, 2005 that weighed 56.25 kg (124 lb). The largest flathead catfish, Pylodictis olivaris, ever caught was in Independence, Kansas, weighing 56 kg (123 lb 9 oz). However, these records pale in comparison to a giant Mekong catfish caught in northern Thailand in May 1, 2005 and reported to the press almost 2 months later, that weighed 293 kg (646 lb). This is the largest giant Mekong catfish caught, but only since Thai officials started keeping records in 1981 . The giant Mekong catfish are not well studied since they live in developing countries and it is quite possible that they can grow even larger.
Catfish belong to a superorder called the Ostariophysi, which also includes the Cypriniformes, Characiformes, Gonorynchiformes and Gymnotiformes (although some place Gymnotiformes as a sub-order of Siluriformes). As of 2005 there are 37 catfish families, and around 2,000 species have been described, although this number is in constant flux due to taxonomic work on the order.
In June, 2005, researchers named the 37th family of catfish, Lacantuniidae, only the third new family of fish distinguished in the last 70 years (others being the coelacanth in 1938 and the megamouth shark in 1983). The new species in Lacantuniidae, Lacantunia enigmatica, was found in the Lacantun river in Chiapas, Mexico.
In the southeast of the United States, catfish is an extremely popular food. The fish, mostly channel catfish and blue catfish, are found in most waterways in the region. The fish is typically breaded with cornmeal and fried. Catfish are easy to farm in warm climates, leading to inexpensive and safe food in local grocers. This has further increased its popularity in the U.S. as food.
A popular sport among some in these areas is noodling, which involves catching catfish using only one's bare hands by luring a catfish to bite the noodler's hand and then grabbing the fish's gills.
- In the United States, June 25 is National Catfish Day.
- Iridescent Shark
- ^ J.E. Morris (October 1993). "Pond Culture of Channel Catfish in the North Central Region". North Central Regional Aquaculture Center. Retrieved on 2006-06-28.
- ^ Grizzly Bear-Size Catfish Caught in Thailand. National Geographic News. Retrieved on 2006-07-14.