#siluriformes

Siluriformes are the vertebrate order with the largest number of venomous species. Most species are not dangerous to humans, but members of the family Plotosidae and of the genus Heteropneustes have a powerful venom that may hospitalize humans who receive a sting. The Striped Eel Catfish (Plotosus lineatus) has a sting which can cause mild to severe reactions in humans, including death, though no human deaths have been recorded as a result of a Striped Eel Catfish sting.

Members of the Malapteruridae family lack the spines of other catfish, instead opting for the ability to generate electricity in defense. Some species can deliver a shock of up to 350 volts from their electric organs. Electric catfish are found in tropical Africa and the Nile River, where they were well-known by Ancient Egyptians. The Early Dynastic King Narmer (meaning “painful/raging/angry catfish”) was named after the animal, sometimes with the abbreviation of just a catfish symbol.

Catfish have one of the largest ranges in size within a single Actinopterygiian order. Many catfish are 12 cm (4.7 in) or less, but some reach truly massive sizes. Record holders include the Wels Catfish (Silurus glanis), the Mekong Giant Catfish (Pangasianodon gigas) (image 1), and the Piraíba (Brachyplatystoma filamentosum), which can all reach over 2 m (6.6 ft) long, with the Piraíba getting up to 3.6 metres (12 ft) long and weighing 200 kilograms (440 lb). Myths exist of some of these giant catfishes being man-eaters, though verifiable evidence of this has yet to be produced.

The Mekong Giant Catfish is critically endangered due to overfishing, as well as loss of water quality due to development and dams. Fishing for wild Mekong Giant Catfish is illegal in the wild in Thailand, Laos, and Cambodia, but the bans appear to be ineffective and the fish continue to be caught in all three countries. Millions of tons of the fish are harvested in Cambodia every year, with even spawning fish being overharvested. Commercial international trade of wild-caught specimens is banned. Thailand is the only country to allow fishing for private stocks of Mekong Giant Catfish, and breeding for the aquarium trade.

In the Southern United States, catfish species may be known by a variety of slang names, such as "mud cat", "polliwogs", or "chuckleheads". These nicknames are not standardized, so one area may call a Bullhead Catfish (genus Ameiurus) by the nickname "chucklehead", while in another state or region, “chucklehead” refers to the Blue Catfish (Ictalurus furcatus).

The Walking Catfish (Clarias batrachus) is named for its ability to "walk" and wiggle across dry land, which it does to find food and disperse to better environments. Walking Catfish normally live in slow-moving and often stagnant water in ponds, swamps, streams, and rivers, as well as in flooded rice paddies or temporary pools that may dry up. When this happens, the Walking Catfish simply “walks” to a new aquatic environment.

The Candiru (Vandellia cirrhosa) is a parasitic freshwater catfish with a reputation for swimming up the urethra of bathing humans… however this is most likely a myth. Historical stories of the Candiru entering human orifices seem to have arisen from the trend of European explorers, doctors, and missionaries regularly using exaggerated accounts of native people to advance their economic and social status through fantastical writings. In reality, the tiny catfish slips into the gills of larger fish and latches onto the fish’s gill chamber, drinking the host’s blood. Once it is full, it releases its bite and swims away. In most cases, the host fish do not seem to be badly wounded by the tiny vampire.

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. Channel Catfish (Ictalurus punctatus) support a $450 million/yr aquaculture industry. Catfish raised in inland tanks or channels are usually considered safe for the environment, since their waste and disease can be contained and not spread to the wild.

In 2003, The United States Congress passed a law preventing imported catfish from being labeled as catfish, saying that it would put pressure on the U.S. catfish industry. Thus, the Vietnamese shark-catfish Pangasius bocourti is called Basa, “Basa Fish”, or “Swai”.

In the mythology of the Japanese Shinto religion, earthquakes are caused by a giant underground catfish called Namazu. The god Takemikazuchi restrains the catfish underneath a stone. When the Kashima-god lets his guard fall, Namazu thrashes about, causing violent earthquakes. After the 1855 Edo earthquake Namazu-e were printed giving more popularity to the catfish kami. In one catfish print the divine white horse of Amaterasu is depicted knocking down the earthquake-causing catfish.

Catfish are quite popular in the home aquarium trade, and are often sold as bottom feeders and algae eaters. Most popular are species of the genus Corydoras: small, schooling catfish beloved for their small size and peaceful nature. Species of the family Loricariidae (image 4) are often called “plecos”, due to the popularity of the Suckermouth Catfish (Hypostomus plecostomus). They are often lauded as “algae eaters” and “tank cleaners”, but the diet of pleco species vary, some eating more meat, invertebrates, or wood, and they contribute more waste to the tank than algae they ingest. Some species of pleco (such as the eponymous H. plecostomus) get to be quite large, and when they outgrow their tanks may end up dumped into bodies of water outside of their native habitat, where they can become invasive species. It is important to research the full life history of any fish you intend to keep, and not keep them for a single “task”.