Catfish

Catfish

Overview
Catfishes are a diverse group of ray-finned
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...

 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...

. Named for their prominent barbel
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...

s, which resemble a cat's whisker
Whisker
Whisker may refer to:* an element of box plots* cat's whisker diode, a thin wire used as a contact on a crystal radio receiver* facial hair, hair on the face of a human* vibrissa, a hair on the face of a mammal, used for sensing the surroundings...

s, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish
Mekong giant catfish
The Mekong giant catfish, Pangasianodon gigas, is a species of catfish in the shark catfish family , native to the Mekong basin in Southeast Asia.-Species characteristics:...

 from Southeast Asia and the second longest, the wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...

 of Eurasia, to detritivore
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...

s (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru
Candirú
‎Candiru or candirú , also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River...

, Vandellia cirrhosa. There are armour-plated types and also naked types, neither having scales.
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Encyclopedia
Catfishes are a diverse group of ray-finned
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...

 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...

. Named for their prominent barbel
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...

s, which resemble a cat's whisker
Whisker
Whisker may refer to:* an element of box plots* cat's whisker diode, a thin wire used as a contact on a crystal radio receiver* facial hair, hair on the face of a human* vibrissa, a hair on the face of a mammal, used for sensing the surroundings...

s, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish
Mekong giant catfish
The Mekong giant catfish, Pangasianodon gigas, is a species of catfish in the shark catfish family , native to the Mekong basin in Southeast Asia.-Species characteristics:...

 from Southeast Asia and the second longest, the wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...

 of Eurasia, to detritivore
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...

s (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru
Candirú
‎Candiru or candirú , also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River...

, Vandellia cirrhosa. There are armour-plated types and also naked types, neither having scales. Despite their name, not all catfish have prominent barbels; members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

 or fished for food. Many of the smaller species, particularly the genus Corydoras
Corydoras
Members of the South American Corydoras genus are freshwater temperate and tropical catfish in the armored catfish family , and are commonly referred to as corydorases, cories, or cory catfish.-Taxonomy:...

, are important in the aquarium hobby
Fishkeeping
Fishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond. There is also a fishkeeping industry, as a branch of agriculture.-Types of fishkeeping systems:...

.

Distribution and habitat


Extant catfish species live in inland or coastal waters of every continent except Antarctica. Catfish have inhabited all continents at one time or another. Catfish are most diverse in tropical
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately  N and the Tropic of Capricorn in the southern hemisphere at  S; these latitudes correspond to the axial tilt of the Earth...

 South America, Africa, and Asia. More than half of all catfish species live in the Americas. They are the only ostariophysan
Ostariophysi
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains almost 8,000 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all major continents except Antarctica...

s that have entered freshwater
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

 habitats in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, Australia, and New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

.

They are found in freshwater environments, though most inhabit shallow, running water. Representatives of at least eight families are hypogean (live underground) with three families that are also troglobitic
Troglobite
Troglobites are small cave-dwelling animals that have adapted to their dark surroundings. Troglobite species include spiders, insects, fish and others. They live permanently underground and cannot survive outside the cave environment. Troglobite adaptations and characteristics include a heightened...

 (inhabiting caves). One such species is Phreatobius cisternarum
Phreatobius cisternarum
Phreatobius cisternarum is a species of catfish in the genus Phreatobius. This Brazilian fish is one of the few fish species that live underground in phreatic habitats. It has proved problematic in its classification, which remains uncertain....

, known to live underground in phreatic
Phreatic
The term phreatic is used in Earth sciences to refer to matters relating to ground water below the water table . The term 'phreatic surface' indicates the location where the pore water pressure is under atmospheric conditions...

 habitats. Numerous species from the families Ariidae
Ariidae
The Ariidae or ariid catfish are a family of catfish that mainly live in marine waters with many freshwater and brackish water species. They are found worldwide in tropical to warm temperate zones.-Taxonomy:...

 and Plotosidae, and a few species from among the Aspredinidae
Aspredinidae
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes.-Distribution:Aspredinids are found throughout the major tropical rivers of South America...

 and Bagridae
Bagridae
Bagridae are a family of catfish that originate from Africa and Asia from Japan to Borneo. These fish are commonly known as naked catfishes or bagrid catfishes.Large Bagrids are important as food fish. Some species are kept as aquarium fishes....

, are found in salt water.

External anatomy of catfish


Most catfish are bottom feeders. In general, they are negatively buoyant
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

, which means that they will usually sink rather than float due to a reduced gas bladder
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...

 and a heavy, bony head. Catfish have a variety of body shapes, though most have a cylindrical body with a flattened ventrum
Anatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

 to allow for benthic feeding.

A flattened head allows for digging through the substrate as well as perhaps serving as a hydrofoil
Hydrofoil
A hydrofoil is a foil which operates in water. They are similar in appearance and purpose to airfoils.Hydrofoils can be artificial, such as the rudder or keel on a boat, the diving planes on a submarine, a surfboard fin, or occur naturally, as with fish fins, the flippers of aquatic mammals, the...

. Most have a mouth that can expand to a large size and contains no incisiform
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...

 teeth; catfish generally feed through suction
Suction
Suction is the flow of a fluid into a partial vacuum, or region of low pressure. The pressure gradient between this region and the ambient pressure will propel matter toward the low pressure area. Suction is popularly thought of as an attractive effect, which is incorrect since vacuums do not...

 or gulping rather than biting and cutting prey. However, some families, notably Loricariidae
Loricariidae
Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...

 and Astroblepidae, have a suckermouth
Suckermouth
In fishes, a suckermouth is a ventrally-oriented mouth adapted for grazing on algae and small organisms that grow on submerged objects....

 that allows them to fasten themselves to objects in fast-moving water. Catfish also have a maxilla reduced to a support for 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...

; this means that they are unable to protrude their mouths as other fish such as carp
Carp
Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

.

Catfish may have up to four pairs of barbels: nasal, maxillary (on each side of mouth), and two pairs of chin barbels, although pairs of barbels may be absent, depending on the species. Catfish also have chemoreceptors across their entire bodies, which means they "taste" anything they touch and "smell" any chemicals in the water. "In catfish, gustation plays a primary role in the orientation and location of food". Because their barbels and chemoreception are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysan
Ostariophysi
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains almost 8,000 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all major continents except Antarctica...

s, they are characterized by the presence of a Weberian apparatus
Weberian apparatus
The Weberian apparatus is an anatomical structure that connects the swim bladder to the auditory system in fishes belonging to the Superorder Ostariophysi. When it is fully developed in adult fish, the elements of the apparatus are sometimes collectively referred to as the Weberian ossicles...

. Their well-developed Weberian apparatus and reduced gas bladder
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...

 allow for improved hearing
Hearing (sense)
Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...

 as well as sound production.

Catfish have no scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

s; their bodies are often naked. In some species, the 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...

-covered skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 is used in cutaneous respiration
Respiration (physiology)
'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...

, where the fish breathes through its skin. In some catfish, the skin is covered in bony plates called scutes
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

; some form of body armor appears in various ways within the order. In loricarioids
Loricarioidea
Loricarioidea is a superfamily of catfishes . It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae...

 and in the Asian genus Sisor
Sisor
Sisor is a genus of catfishes of the family Sisoridae. It includes five species, S. barakensis, S. chennuah, S. rabdophorus, S. rheophilus, and S. torosus.-Taxonomy:...

, the armor is primarily made up of one or more rows of free dermal
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...

 plates. Similar plates are found in large specimens of Lithodoras. These plates may be supported by vertebral process
Process (anatomy)
In anatomy, a process is a projection or outgrowth of tissue from a larger body. The vertebra has several kinds of processes,such as: transverse process, prezygapophysis, postzygapophysis.-Examples:Examples of processes include:...

es, as in scoloplacids and in Sisor, but the processes never fuse to the plates or form any external armor. By contrast, in the subfamily Doumeinae (family Amphiliidae) and in hoplomyzontines (Aspredinidae
Aspredinidae
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes.-Distribution:Aspredinids are found throughout the major tropical rivers of South America...

), the armor is formed solely by expanded vertebral processes that form plates. Finally, the lateral armor of doradids
Doradidae
Doradidae is a family of catfishes also known as thorny catfishes or talking catfishes. These fish are native to South America, primarily in Brazil, Peru, and the Guianas.Doradids are omnivorous.-Taxonomy:...

, Sisor, and hoplomyzontines consists of hypertrophied lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...

 ossicles with dorsal and ventral lamina
Lamina (algae)
A Lamina in the algae is a generally flattened structure which typically forms the principal bulk of macroscopic plants. It is often developed into specialised organs such as flotation bladders and reproductive organs....

.


All catfish, except members of Malapteruridae (electric catfish), possess a strong, hollow, bonified leading spine-like ray on their dorsal
Dorsal 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 pectoral fins. As a defense, these spines may be locked into place so that they stick outwards, which can inflict severe wounds. In several species catfish can use these fin rays to deliver a stinging protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 if the fish is irritated. This venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...

 is produced by gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...

ular cells in the epidermal tissue covering the spines. In members of the family Plotosidae, and of the genus Heteropneustes
Heteropneustes
Heteropneustes is a genus of catfishes of the family Clariidae. It includes two species, H. fossilis and H. kemratensis. The species H. microps has been synonymized with H. fossilis. The validity of the name H. longipectoralis for a possible third species is unknown.H. fossilis is widely...

, this protein is so strong it may hospitalize humans, those unfortunate enough to receive a sting; in Plotosus lineatus
Plotosus
Plotosus is a genus of catfishes of the family Plotosidae. It includes six species, P. canius, P. fisadoha, P. limbatus, P. lineatus, P. nkunga, P. papuensis.-Distribution:...

, the stings may result in death.

Juvenile catfish, like most fish, have relatively large heads, eyes and posterior median fins in comparison to larger, more mature individuals. These juveniles can be readily placed in their families, particularly those with highly derived fin or body shapes; in some cases identification of the genus is possible. As far as known for most catfish, features that are often characteristic of species such as mouth and fin positions, fin shapes, and barbel lengths show little difference between juveniles and adults. For many species, pigmentation pattern is also similar in juveniles and adults. Thus, juvenile catfishes generally resemble and develop smoothly into their adult form without distinct juvenile specializations. Exceptions to this are the ariid catfishes, where the young retain yolk sacs late into juvenile stages, and many pimelodids, which may have elongated barbels and fin filaments or coloration patterns.

Sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

 is reported in about half of all families of catfish. The modification of the anal fin into an intromittent organ
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

 (in internal fertilizers) as well as accessory structures of the reproductive apparatus (in both internal and external fertilizers) have been described in species belonging to 11 different families.

Size


Catfish have one of the greatest ranges in size within a single order of bony fish
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...

. Many catfish have a maximum length of under 12 cm. Some of the smallest species of Aspredinidae
Aspredinidae
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes.-Distribution:Aspredinids are found throughout the major tropical rivers of South America...

 and Trichomycteridae
Trichomycteridae
Trichomycteridae is a family of catfishes commonly known as the pencil or parasitic catfishes. This family includes the infamous candiru fish, feared by some people for its alleged habit of entering into the urethra of humans....

 reach sexual maturity at only 1 centimetre (0.393700787401575 in).

The wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...

, Silurus glanis, is the only native catfish species of Europe, besides the much smaller related Aristotle's catfish
Aristotle's catfish
Aristotle's catfish is a species of fish in the Siluridae family. It is endemic to Greece. Its natural habitat is freshwater lakes. It is threatened by habitat loss.-Source:...

 found in Greece. Mythology
Mythology
The term mythology can refer either to the study of myths, or to a body or collection of myths. As examples, comparative mythology is the study of connections between myths from different cultures, whereas Greek mythology is the body of myths from ancient Greece...

 and literature record wels catfish of astounding proportions, yet to be proven scientifically. The average size of the species is about 1.2–1.6 m (3.9–5.2 ft), and fish more than 2 metres (6.6 ft) are very rare. The largest specimens on record measure more than 2.5 metres (8.2 ft) in length and sometimes exceeded 100 kilograms (220.5 lb).

The largest Ictalurus furcatus, caught in the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

 on July 20, 2010, weighed 130 pounds (59 kg). The largest flathead catfish
Flathead catfish
The flathead catfish , also called the yellow cat, opelousas, and shovelhead cat, are large North American freshwater catfish. This is the only species of the genus Pylodictis...

, Pylodictis olivaris, ever caught was in Independence, Kansas
Independence, Kansas
Independence is a city in and the county seat of Montgomery County, Kansas, United States. As of the 2010 census, the city population was 9,483.-Geography:...

, weighing 123 lb 9 oz (56.0 kg). In July 2009, a catfish weighing 193 pounds was caught in the River Ebro, Spain, by an 11-year old British schoolgirl. However, these records pale in comparison to a giant Mekong catfish
Mekong giant catfish
The Mekong giant catfish, Pangasianodon gigas, is a species of catfish in the shark catfish family , native to the Mekong basin in Southeast Asia.-Species characteristics:...

 caught in northern 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...

 on May 1, 2005 and reported to the press almost 2 months later that weighed 293 kilograms (646 lb). This is the largest giant Mekong catfish caught 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.

Internal anatomy


In many catfish, the humeral process is a bony process extending backward from the pectoral girdle immediately above the base of the pectoral fin. It lies beneath the skin where its outline may be determined by dissecting the skin or probing with a needle.

The retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...

 of catfish are composed of single cone
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...

s and large rod
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...

s. Many catfish have a tapetum lucidum
Tapetum lucidum
The tapetum lucidum is a layer of tissue in the eye of many vertebrate animals....

 which may help enhance photon
Photon
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

 capture and increase low-light sensitivity. Double cone
Double cone
Double cones , also known as twin cones in some literature, are two cone cells joined together that may also be coupled optically/electrically...

s, though present in most teleosts are absent from catfish.

The anatomical organization of the testis
Testicle
The testicle is the male gonad in animals. Like the ovaries to which they are homologous, testes are components of both the reproductive system and the endocrine system...

 in catfish is variable among the families of catfish, but the majority of them present fringed testis: Ictaluridae, Claridae, Auchenipteridae, Doradidae, Pimelodidae, and Pseudopimelodidae. In the testes of some species of Siluriformes, organs and structures such as a spermatogenic cranial region and a secretory caudal region are observed, in addition to the presence of seminal vesicles in the caudal region. The total number of fringes and their length are different in the caudal and cranial
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 portions between species. Fringes of the caudal region may present tubules, in which the lumen is filled by secretion and spermatozoa
Spermatozoon
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...

. Spermatocysts are formed from cytoplasmic extensions of Sertoli cell
Sertoli cell
A Sertoli cell is a 'nurse' cell of the testes that is part of a seminiferous tubule.It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes.-Functions:...

s; the release of spermatozoa is allowed by breaking of the cyst walls.

The occurrence of seminal vesicle
Seminal vesicle
The seminal vesicles or vesicular glands are a pair of simple tubular glands posteroinferior to the urinary bladder of male mammals...

s, in spite of their interspecific variability in size, gross morphology and function, has not been related to the mode of fertilization. They are typically paired, multi-chambered, and connected with the sperm duct, and have been reported to play a glandular and a storage function. Seminal vesicle secretion may include steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

s and steroid glucuronides, with hormonal and pheromonal functions, but it appears to be primarily constituted of mucoproteins, acid mucopolysaccharides, and phospholipids.

Fish ovaries may be of two types: gymnovarian or cystovarian. In the first type, the oocytes are released directly into the coelom
Coelom
The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...

ic cavity and then eliminated. In the second type, the oocytes are conveyed to the exterior through the oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...

. Many catfish are cystovarian in type, including Pseudoplatystoma corruscans, P. fasciatum, Lophiosilurus alexandri
Lophiosilurus alexandri
Lophiosilurus alexandri is a species of catfish of the family Pseudopimelodidae, and the only species of the monotypic genus Lophiosilurus.-Distribution and habitat:...

, and Loricaria lentiginosa.

Catfish as food



Catfish have been widely caught and farmed for food for hundreds of years in Africa, Asia, Europe, and North America. Judgments as to the quality and flavor vary, with some food critics considering catfish as being excellent food, others dismiss them as watery and lacking in flavor. In Central Europe
Central Europe
Central Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...

, catfish were often viewed as a delicacy to be enjoyed on feast days and holidays. Migrants from Europe and Africa to the United States brought along this tradition, and in the Southern United States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...

 catfish is an extremely popular food. The most commonly eaten species in the United States are the channel catfish
Channel catfish
Channel catfish, Ictalurus punctatus, is North America's most numerous catfish species. It is the official fish of Missouri, Iowa, Nebraska, Kansas, and Tennessee, and is informally referred to as a "channel cat". In the United States they are the most fished catfish species with approximately 8...

 and blue catfish
Blue catfish
The blue catfish, Ictalurus furcatus, is one of the largest species of North American catfish. Blue catfish are distributed primarily in the Mississippi River drainage including the Missouri, Ohio, Tennessee, and Arkansas rivers...

, both of which are common in the wild and increasingly widely farmed. Farm-raised catfish became such a staple of the diet of the United States that on June 25, 1987, President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

 established National Catfish Day
National Catfish Day
National Catfish Day is a national observance of the United States celebrating "the value of farm-raised catfish." The day was designated as June 25, 1987, by President Ronald Reagan, who issued the Presidential Proclamation after the U.S...

 to recognize "the value of farm-raised catfish."

Catfish is eaten in a variety of ways; in Europe it is often cooked in similar ways to carp
Carp
Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

, but in the United States it is typically crumbed with cornmeal
Cornmeal
Cornmeal is flour ground from dried maize or American corn. It is a common staple food, and is ground to fine, medium, and coarse consistencies. In the United States, the finely ground cornmeal is also referred to as cornflour. However, the word cornflour denotes cornstarch in recipes from the...

 and fried.

In 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...

 catfish are usually served grilled in street stalls called warung
Warung
A warung is a type of small family-owned business — often a casual shop, usually café — in Indonesia and Malaysia...

 and eaten with vegetables and soy sauce
Pecel
Pecel is an Indonesian sauce based on chillies, peanuts, tamarind and coconut sugar. It is commonly served over boiled vegetables. It is similar to the sauce used in Gado-gado.-External links:*...

; the dish is called Pecel Lele. Catfish can also be eaten with chili sambal
Sambal
Sambal is a chili based sauce which is normally used as a condiment. Sambals are popular in Indonesia, Malaysia, Singapore, the southern Philippines and Sri Lanka, as well as in the Netherlands and in Suriname through Javanese influence. It is typically made from a variety of chili peppers and is...

 as Lele Penyet (minced catfish). (Lele is the 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...

n word for catfish)

In Malaysia catfish, called "Ikan Keli", is fried with spices or grilled and eaten with tamarind and Thai chillies gravy and also is often eaten with steamed rice. In the Indian states of West Bengal
West Bengal
West Bengal is a state in the eastern region of India and is the nation's fourth-most populous. It is also the seventh-most populous sub-national entity in the world, with over 91 million inhabitants. A major agricultural producer, West Bengal is the sixth-largest contributor to India's GDP...

, Assam
Assam
Assam , also, rarely, Assam Valley and formerly the Assam Province , is a northeastern state of India and is one of the most culturally and geographically distinct regions of the country...

 and 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...

 Catfish (locally known as Magur) is eaten as a favored delicacy during the monsoons. Catfish, locally known as thedu or etta in Malayalam, is very famous in Indian State, kerala
Kerala
or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....

. It is also believed that catfish meat helps in blood purification. Catfish curry is consumed in these parts to bring up faster recovery to patients suffering from fever or other ailments.

Catfish is high in Vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

. Farm-raised catfish contains low levels of omega-3 fatty acids and a much higher proportion of omega-6 fatty acids.

Vietnamese catfish cannot be legally marketed as catfish in the US, and is subsequently referred to as swai or basa
Basa fish
The basa fish, Pangasius bocourti, is a type of catfish in the family Pangasiidae. Basa are native to the Mekong River Delta in Vietnam and Chao Phraya basin in Thailand. These fish are important food fish with an international market. They are often labeled in North America and Australia as "basa...

  Only fish of the family Ictaluridae may be marketed as catfish in the United States.

As catfish lack scales, they are judged to not be kosher and may not be eaten by observant Jews, some Christians who follow the Torah
Torah
Torah- A scroll containing the first five books of the BibleThe Torah , is name given by Jews to the first five books of the bible—Genesis , Exodus , Leviticus , Numbers and Deuteronomy Torah- A scroll containing the first five books of the BibleThe Torah , is name given by Jews to the first five...

, and observant Muslims of various schools.

Catfish in Hungary is often cooked in paprika souce (Harcsapaprikás) typical to Hungarian cuisine. It is traditionally served with pasta smothered with curd cheese (túrós csusza
Túrós csusza
Turos csusza is a Hungarian savoury curd cheese noodle dish or cottage cheese noodle dish made with small home made noodles or pasta.Turoscsusza is a traditional pasta dish of the Hungarian cuisine....

).

Aquaculture



Catfish are easy to farm in warm climates, leading to inexpensive and safe food at local grocers. About 60% of U.S. farm-raised catfish are grown within a 65-mile (100-km) radius of Belzoni, Mississippi
Belzoni, Mississippi
Belzoni is a city in Humphreys County, Mississippi, in the Mississippi Delta region, on the Yazoo River. The population was 2,663 at the 2000 census. It is the county seat of Humphreys County...

. Ictalurids
Ictaluridae
The Ictaluridae, sometimes called Ictalurids, are a family of catfish native to North America, where they are important food fish and sometimes as a sport fish. They include fish commonly known as bullheads, madtoms, channel catfish, and blue catfish....

 are cultivated in North America (especially in the Deep South
Deep South
The Deep South is a descriptive category of the cultural and geographic subregions in the American South. Historically, it is differentiated from the "Upper South" as being the states which were most dependent on plantation type agriculture during the pre-Civil War period...

, with Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...

 being the largest domestic catfish producer). Channel catfish
Channel catfish
Channel catfish, Ictalurus punctatus, is North America's most numerous catfish species. It is the official fish of Missouri, Iowa, Nebraska, Kansas, and Tennessee, and is informally referred to as a "channel cat". In the United States they are the most fished catfish species with approximately 8...

 (Ictalurus punctatus) supports a $450 million/yr aquaculture industry.

Catfish raised in inland tanks or channels are considered safe for the environment, since their waste and disease should be contained and not spread to the wild.

In Asia, many catfish species are important as food. Several walking catfish
Walking catfish
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...

 (Clariidae) and shark catfish
Shark catfish
The shark catfishes are a family, the Pangasiidae, of catfishes found in fresh and brackish waters across southern Asia, from Pakistan to Borneo. Among the 30-odd members of this family is the plant-eating, endangered Mekong giant catfish Pangasianodon gigas, one of the largest known freshwater...

 (Pangasiidae) species are heavily cultured in Africa and Asia. Exports of one particular shark catfish species from Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

, Pangasius bocourti, has met with pressures from the U.S. catfish industry. In 2003, The United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 passed a law preventing the imported fish from being labeled as catfish. As a result, the Vietnamese exporters of this fish now label their products sold in the U.S. as "basa fish." Trader Joe's has labeled frozen fillets of Vietnamese Pangasius hypophthalmus as "striper."

There is a large and growing ornamental fish trade, with hundreds of species of catfish, such as Corydoras
Corydoras
Members of the South American Corydoras genus are freshwater temperate and tropical catfish in the armored catfish family , and are commonly referred to as corydorases, cories, or cory catfish.-Taxonomy:...

and armored suckermouth catfish
Loricariidae
Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...

 (often called pleco
Plecostomus
Hypostomus plecostomus is the scientific name for a type of freshwater tropical Central and South American fish belonging to the family Loricariidae. They are large algae eaters, and to differentiate them from small algae eaters, they are often referred to as plecostomus, often abbreviated as...

s), being a popular component of many aquaria
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

. Other catfish commonly found in the aquarium trade are banjo catfish
Aspredinidae
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes.-Distribution:Aspredinids are found throughout the major tropical rivers of South America...

, talking catfish
Doradidae
Doradidae is a family of catfishes also known as thorny catfishes or talking catfishes. These fish are native to South America, primarily in Brazil, Peru, and the Guianas.Doradids are omnivorous.-Taxonomy:...

, and long-whiskered catfish
Pimelodidae
Pimelodidae, commonly known as the long-whiskered catfishes, is a family of catfishes .-Taxonomy:Pimelodidae has undergone much revision. Currently, the family contains about 30 genera and about 90 recognized and known but unnamed species...

.

Catfish as invasive species



Representatives of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Ictalurus
Ictalurus
Ictalurus is a genus of catfishes of the family Ictaluridae. It includes the well-known channel catfish and blue catfish ....

have been introduced into European waters in the hope of obtaining a sporting and food resource. However, the European stock of American catfishes has not achieved the dimensions of these fish in their native waters, and have only increased the ecological pressure on native European fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...

. Walking catfish
Walking catfish
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...

 have also been introduced in the freshwaters of Florida, with the voracious catfish becoming a major alien pest there. Flathead catfish
Flathead catfish
The flathead catfish , also called the yellow cat, opelousas, and shovelhead cat, are large North American freshwater catfish. This is the only species of the genus Pylodictis...

, Pylodictis olivaris, is also a North American pest on Atlantic slope drainages. Pterygoplichthys
Pterygoplichthys
Pterygoplichthys is a genus of the armored catfish family Loricariidae. These fish are commonly known as sailfin armoured catfish or sailfin plecs.-Taxonomy:This genus was described in 1858 by Theodore Nicholas Gill...

species, released by aquarium fishkeepers, have also established feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...

 populations in many warm waters around the world.

Dangers to humans


While the vast majority of catfish are harmless to humans, a few species are known to present some risk. Perhaps the most notorious of these is the Candiru
Candirú
‎Candiru or candirú , also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River...

, due to the way it is reputed to parasitize the urethra, though there is only one well-documented case of a candiru attack on a human.

Since 2007, the Goonch catfish
Bagarius
Bagarius is a genus of catfishes of the family Sisoridae. It includes four extant species, B. bagarius, B. rutilus, B. suchus, and B. yarelli , and one extinct species, B. gigas.-Distribution:Bagarius species inhabit south and southeast Asia...

 has also gained attention following a series of fatal underwater attacks
Kali River goonch attacks
The Kali River goonch attacks were a series of fatal attacks on humans believed to be perpetrated by man-eating goonch catfish in three villages on the banks of the Kali River in India and Nepal, between 1998 and 2007...

 which have been alleged by biologist Jeremy Wade
Jeremy Wade
Jeremy John Wade is a British biologist, television presenter, extreme angler and writer specializing in travel and natural history. He is best known for his television series River Monsters, produced by Icon Films...

 to have been from unusually large goonch.

The Wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...

 has also been reputed to kill humans (especially young children), and while there are no documented cases of fatalities, larger specimens are known to cause serious injuries in rare instances. In addition, other species are reputed to be dangerous to humans as well, but with less definitive evidence.

Many catfish species have "stings" (actually non-venomous in most cases) embedded behind their fins; thus precautions must be taken when handling them.

Taxonomy


The catfishes are a monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 group. This is supported by molecular evidence.

Catfish belong to a superorder called the Ostariophysi
Ostariophysi
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains almost 8,000 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all major continents except Antarctica...

, which also includes the Cypriniformes
Cypriniformes
The Cypriniformes are an order of ray-finned fish, including the carps, minnows, loaches and relatives. This order contains 5-6 families, over 320 genera, and more than 3,250 species, with new species being described every few months or so, and new genera being recognized regularly...

, Characiformes
Characiformes
The Characiformes are an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, there are a few thousand different species, including the well-known piranha and tetras.-Taxonomy:...

, Gonorynchiformes
Gonorynchiformes
Gonorynchiformes is an order of ray-finned fish that includes the important food source, the milkfish , and a number of lesser-known types, both marine and freshwater....

 and Gymnotiformes
Gymnotiformes
The Gymnotiformes are a group of teleost bony fishes commonly known as the Neotropical or South American knifefishes. They have long bodies and swim using undulations of their elongated anal fin...

, a superorder characterized by the Weberian apparatus
Weberian apparatus
The Weberian apparatus is an anatomical structure that connects the swim bladder to the auditory system in fishes belonging to the Superorder Ostariophysi. When it is fully developed in adult fish, the elements of the apparatus are sometimes collectively referred to as the Weberian ossicles...

. Some place Gymnotiformes as a sub-order of Siluriformes, however this is not as widely accepted. Currently, the Siluriformes are said to be the sister group to the Gymnotiformes, though this has been debated due to more recent molecular evidence. there are about 36 extant catfish families, and about 3,093 extant species have been described. This makes the catfish order the second or third most diverse vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

 order; in fact, 1 out of every 20 vertebrate species is a catfish.

The taxonomy of catfishes is quickly changing. In a 2007 and 2008 paper, Horabagrus
Horabagrus
Horabagrus is a small genus of catfishes . It comprises two species, H. brachysoma and H. nigricollaris. H. brachysoma is an important food fish, and both species are available as aquarium fish.-Common names:...

, Phreatobius
Phreatobius
Phreatobius is a genus of catfishes .-Taxonomy:For quite some time Phreatobius cisternarum was the only species in the genus...

, and Conorhynchos were not classified under any current catfish families. There is disagreement on the family status of certain groups; for example, Nelson (2006) lists Auchenoglanididae and Heteropneustidae as separate families, while the All Catfish Species Inventory (ACSI) includes them under other families. Also, FishBase
FishBase
FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...

 and the Integrated Taxonomic Information System
Integrated Taxonomic Information System
The Integrated Taxonomic Information System is a partnership designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagency group within the U.S...

 lists Parakysidae as a separate family, while this group is included under Akysidae by both Nelson (2006) and ACSI. Many sources do not list the recently revised family Anchariidae
Anchariidae
Anchariidae is a family of catfishes order. This small family contains two genera, Ancharius and Gogo. Anchariids are a strictly freshwater group endemic to Madagascar. Anchariids are characterized by the presence of fringed barbels and a reduced anterior nuchal plate.Traditionally, Ancharius is...

. The family Horabagridae, including Horabagrus, Pseudeutropius, and Platytropius, is also not shown by some authors but presented by others as a true group. Thus, the actual number of families differs between authors. The species count is in constant flux due to taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 work as well as description of new species. On the other hand, our understanding of catfishes should increase in the next few years due to work by the ACSI.

The rate of description of new catfishes is at an all-time high. Between 2003 and 2005, over 100 species have been named, a rate three times faster than that of the past century. In June, 2005, researchers named the newest family of catfish, Lacantuniidae, only the third new family of fish distinguished in the last 70 years (others being the coelacanth
Coelacanth
Coelacanths are members of an order of fish that includes the oldest living lineage of Sarcopterygii known to date....

 in 1938 and the megamouth shark
Megamouth shark
The megamouth shark, Megachasma pelagios, is an extremely rare species of deepwater shark. Since its discovery in 1976, only a few megamouth sharks have been seen, with 53 specimens known to have been caught or sighted as of 2011, including three recordings on film...

 in 1983). The new species in Lacantuniidae, Lacantunia enigmatica
Lacantunia enigmatica
The Chiapas catfish, Lacantunia enigmatica, is an unusual species of catfish newly described in 2005 from the Lacantún River in the Mexican state of Chiapas. While discovery of an undescribed species of catfish is not uncommon, discovery of a new family-level taxon of any vertebrate group is a...

, was found in the Lacantun river
Lacantún River
-References:*Atlas of Mexico, 1975 .*The Prentice Hall American World Atlas, 1984.*Rand McNally, The New International Atlas, 1993....

 in the Mexican state of Chiapas
Chiapas
Chiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...

.

According to morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 data, Diplomystidae is usually considered to be the most primitive of catfishes and the sister group
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 to the remaining catfishes, grouped in a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 called Siluroidei. Recent molecular evidence contrasts the prevailing hypothesis, where the suborder Loricarioidei are the sister group to all catfishes, including Diplomystidae (Diplomystoidei) and Siluroidei; though they were not able to reject the past hypothesis, the new hypothesis is not unsupported. Siluroidei was found to be monophyletic without Loricarioid families or Diplomystidae with molecular evidence; morphological evidence is unknown that supports Siluroidei without Loricarioidea.

Below is a list of family relationships by different authors. Lacantuniidae is included in the Sullivan scheme based on recent evidence that places it sister to Claroteidae
Claroteidae
The Claroteidae are a family of catfish found in Africa. This family was separated from Bagridae. However, the monophyly of the family is sometimes contested....

.
EWLINE
Nelson, 2006 Sullivan et al., 2006
  • Unresolved families
    • Cetopsidae
    • Pseudopimelodidae
    • Heptapteridae
    • Cranoglanididae
    • Ictaluridae
  • Loricarioidea
    Loricarioidea
    Loricarioidea is a superfamily of catfishes . It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae...

    • Amphiliidae
    • Trichomycteridae
    • Nematogenyiidae
    • Callichthyidae
    • Scoloplacidae
    • Astroblepidae
    • Loricariidae
  • Sisoroidea
    Sisoroidea
    Sisoroidea is a superfamily of catfishes . It contains the four families Amblycipitidae, Akysidae, Sisoridae, and Erethistidae; many sources also include Aspredinidae. With Aspredinidae, this superfamily includes about 42 genera and 230 species.-Taxonomy:Sisoroidea is sister to the Loricarioidea...

    • Amblycipitidae
    • Akysidae
    • Sisoridae
    • Erethistidae
    • Aspredinidae
  • Doradoidea
    • Mochokidae
    • Doradidae
    • Auchenipteridae
  • Siluroidea
    • Siluridae
    • Malapteruridae
    • Auchenoglanididae
    • Chacidae
    • Plotosidae
    • Clariidae
    • Heteropneustidae
  • Bagroidea
    • Austroglanididae
    • Claroteidae
    • Ariidae
    • Schilbeidae
    • Pangasiidae
    • Bagridae
    • Pimelodidae
  • Unresolved families
    • Cetopsidae
    • Plotosidae
    • Chacidae
    • Siluridae
    • Pangasiidae
  • Suborder Loricarioidei
    • Trichomycteridae
    • Nematogenyiidae
    • Callichthyidae
    • Scoloplacidae
    • Astroblepidae
    • Loricariidae
  • Clarioidea
    • Clariidae
    • Heteropneustidae
  • Arioidea
    • Ariidae
    • Anchariidae
  • Pimelodoidea
    • Pimelodidae
    • Pseudopimelodidae
    • Heptapteridae
    • Conorhynchos
  • Ictaluroidea
    • Ictaluridae
    • Cranoglanididae
  • Doradoidea (sister to Aspredinidae)
    • Doradidae
    • Auchenipteridae
  • "Big Asia"
    • Sisoroidea
      • Amblycipitidae
      • Akysidae
      • Sisoridae
      • Erethistidae
    • Ailia
      Ailia
      Ailia is a genus of catfish in the Schilbeidae family....

      + Laides
      Laides
      Laides is a genus of catfishes of the family Schilbeidae. It includes two species, L. hexanema and L. longibarbis. L. hexanema is distributed in Thailand to Indonesia, in large rivers, including the Mekong. L. longibarbis originates from the Mekong, Mehklong, and Chao Phraya River basins.L...

      (Asian schilbeids)
    • Horabagridae (Horabagrus
      Horabagrus
      Horabagrus is a small genus of catfishes . It comprises two species, H. brachysoma and H. nigricollaris. H. brachysoma is an important food fish, and both species are available as aquarium fish.-Common names:...

      + Pseudeutropius + Platytropius)
    • Bagridae (without Rita
      Rita (genus)
      Rita is a genus of catfishes of the family Bagridae. It includes six extant species, R. chrysea, R. gogra, R. kuturnee, R. macracanthus, R. rita, and R. sacerdotum, and one extinct species, R. grandiscutata.-Distribution:Rita species are found in large rivers throughout the Indian subcontinent and...

      )
  • "Big Africa"
    • Mochokidae
    • Malapteruridae
    • Amphiliidae
    • Claroteidae
    • Lacantuniidae
    • Schilbeidae

  • See also



    • Catfish clonk fishing method Clonk fishing
      Clonk (fishing)
      Clonk is a fishing tool which has been used for catfish fishing for ages mainly in Europe. It represents a stick composed of three parts - handle, fork and heel. Originally it was made of wood but nowadays there are clonks made of plastic or metal too because they are easier to produce than wood....

    • All catfish species inventory