Fish

Catfish

Siluriformes · also called siluriform

Not Evaluated omnivore Rivers & wetlands

Catfish are one of the great success stories of the fish world: more than 3,000 species on every continent, ranging from a translucent parasite a few centimetres long to river monsters as heavy as a person. What ties them together is a set of tools for living in the dark — whiskery feelers, a body that tastes, and spines that lock.

Overview

Catfish are the order Siluriformes, roughly one in ten of all freshwater fish. A catfish typically has a broad flat head, a downturned mouth ringed with flexible barbels, no scales (bare skin or bony plates), and stout spines at the front of the dorsal and pectoral fins. Most are bottom-living in fresh water, feeding at night on anything from algae to whole fish.

Feeling and tasting the dark

The barbels are sensory feelers dense with taste buds, used to find food by touch and taste. And a catfish tastes with its whole skin — taste buds cover the body, so it is sometimes called a swimming tongue. Both adaptations suit an animal that feeds in muddy water and at night.

Spines, and a warning

The locking fin spines make a catfish hard to swallow and hard to hold, and in some species — the madtoms, the striped eel catfish, and others — the spine carries venom that causes intense pain, so anglers handle catfish carefully.

Status

Catfish as an order are Not Evaluated. Most are common and several are farmed heavily for food, but some giant river species such as the Mekong giant catfish are Critically Endangered from dams and overfishing, and a few introduced catfish are invasive.

Catfish: common questions

Why do catfish have whiskers?

The whiskers, properly called barbels, are sensory feelers, and they are the catfish's main tool for finding food. Each barbel is soft and mobile and its surface is packed with taste buds and touch receptors, so the fish can sweep it over the bottom, into crevices, and through mud and detect a worm, a dead fish, or a seed by taste and feel without needing to see it. This is a big advantage for an animal that mostly feeds at night, in turbid water, or on the bottom where light barely reaches. Different catfish families carry different numbers and arrangements of barbels, from a single long pair to several pairs around the mouth and chin.

Can a catfish sting you?

Some can, and even those that cannot can still injure you. Every catfish has a stout, often serrated spine at the front of the dorsal fin and of each pectoral fin, which locks upright and can drive deep into a hand, and the wound tears rather than punctures cleanly because of the serrations, so catfish spine injuries readily become infected. In a number of species, including the North American madtoms and bullheads, the striped eel catfish of the Indo-Pacific, and various others, glandular tissue at the base of the spine adds venom, and the sting causes immediate, intense, throbbing pain, swelling, and sometimes systemic effects. Anglers handle catfish with a firm grip behind the pectoral fins or with a lip grip and gloves.

Are all catfish bottom-dwellers?

Most are, but not all. The typical catfish body, with a flattened head, downturned mouth, barbels, and a heavy build, is that of a bottom feeder, and the majority of species do live on or near the sea or river bed. But the order is so large and varied that there are exceptions, including open-water shoaling catfish such as the shark catfishes, surface-feeding species, and even the upside-down catfish of Africa, which habitually swims belly-up to graze food from the underside of leaves and the water surface. Several catfish are also strong air-breathers, gulping air at the surface, and the walking catfish can travel over wet ground between water bodies.

Why are some big river catfish endangered?

The largest catfish species are freshwater giants that need long stretches of connected river to feed, grow, and migrate to spawning grounds, and they mature slowly and breed at a large size, which makes them very sensitive to disturbance. Dams block their migration routes and change flow and temperature, heavy fishing removes the large breeding adults faster than they can be replaced, and pollution and habitat loss reduce the food and clean water they need. The Mekong giant catfish, once caught throughout the river, is now Critically Endangered and rarely seen, and similar declines affect the giant devil catfish of South Asia and other large species. Some are the focus of captive breeding, release, and protected-area programmes.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published November 1, 2026. Last updated November 1, 2026.

Quick facts

Scientific name: Siluriformes
Diet: Ranges by species from algae and detritus scraped off wood and rock, through insect larvae, worms, snails, and crustaceans, to whole fish and, in the giants, ducks and small mammals; many catfish are opportunists that scavenge and hunt at night
The whiskers: The barbels, up to four pairs, are not stiff bristles but flexible feelers covered in taste buds and touch sensors, used to find and identify food by feel and taste in dark or muddy water where sight is little use
It tastes with its body: A catfish is sometimes called a swimming tongue, because taste buds cover not just the barbels and lips but the whole skin, densest on the flanks and belly, so the fish can detect a food item anywhere along its body
No scales, but sometimes armour: Catfish have bare, often slimy skin instead of scales, and some families replace that with rows of bony plates or scutes, seen in the suckermouth armoured catfish, or plecos, of the aquarium trade
Spines that lock and, sometimes, sting: The leading ray of the dorsal fin and of each pectoral fin is a stiff, often serrated spine that can be locked erect, making the fish hard to swallow and hard to handle, and in some species, such as the striped eel catfish and the North American madtoms, the spine delivers venom that causes intense pain
One of the largest fish groups: There are more than 3,000 catfish species, roughly one in twenty of all fish and one in ten of all freshwater fish, on every continent, with fossils even in Antarctica, and only two families that live in the sea
Giants and a tiny parasite: The order runs from the Mekong giant catfish and the wels at 2 to 3 m and 200 to 300 kg down to the candiru of the Amazon, a translucent parasite a few centimetres long that lodges in the gills of larger fish to feed on blood
Range: Fresh water on every continent except Antarctica, in rivers, lakes, swamps, ditches, caves, and estuaries, plus a small number of species in coastal seas; the greatest diversity is in the rivers of South America, Africa, and South and Southeast Asia.
Conservation status: Not Evaluated ≈ Not assessed as an order; most catfish are common and several are farmed on a huge scale for food, but a number of the large river species, including the Mekong giant catfish and the giant devil catfish, are Critically Endangered from dams, overfishing, and habitat loss, and several introduced catfish have become damaging invaders in the wild