Catfish
A diverse order of ray-finned fish known for whisker-like barbels and lack of scales.
Catfish form the order Siluriformes, a large group of ray-finned fish defined by prominent barbels and scaleless skin. They range from tiny parasitic species to massive river giants, inhabiting freshwater environments worldwide.
- Catfish lack scales, having smooth skin or bony armor instead.
- Barbels act as whiskers, helping fish taste and smell food.
- Fin spines can deliver venomous stings to deter predators.
- Mekong giant catfish can weigh over 290 kilograms.
- About half of all vertebrate species are not catfish.
What it is
Catfish belong to the order Siluriformes within the ray-finned fish group. They are easily recognised by their prominent barbels, which look like a cat’s whiskers, although some species lack these features entirely. Unlike most other fish, catfish have no scales; their bodies are either smooth or covered in bony armour plates. Their heads are often heavy and flattened to help them dig into riverbeds. Most possess a cylindrical shape with a flat underside, allowing them to rest on the substrate. The group includes everything from microscopic parasites to enormous river dwellers.
Where it lives
These fish live in freshwater systems across the globe. They are bottom-feeders that prefer darker or murky waters where their sensory organs excel. Some species have adapted to underground caves, losing their eyesight completely. While most inhabit rivers and lakes, certain families can survive in fast-flowing water using suckermouths. The order is highly diverse, with species found in nearly every freshwater environment, from tropical streams to temperate rivers.
How it lives
Catfish are primarily bottom-dwellers that feed by suction or gulping rather than biting. They rely heavily on chemoreceptors located on their barbels and bodies to taste and smell food in the water. Their eyes are typically small, as vision is less critical than chemical detection. Many species form schools, while others are solitary predators. They lack teeth in many cases, using powerful suction to ingest prey. Predators include larger fish, birds, and mammals that hunt them in shallow waters.
Breeding and life cycle
Reproduction varies widely among catfish families. Some use internal fertilisation, modifying their anal fins into intromittent organs, while others spawn externally. Ovaries may be gymnovarian, releasing eggs directly into the body cavity, or cystovarian, using an oviduct. Seminal vesicles store sperm and produce secretions with hormonal functions. Juveniles generally resemble adults but may retain yolk sacs longer in certain families. Growth rates differ significantly between small parasitic species and large commercial varieties.
Fish and people
Many large catfish species are farmed or caught for food, including Pangasius and Clarias. Smaller species like Corydoras are popular in the aquarium trade. However, some aquarium pets, such as plecos, have become invasive pests when released into local waters. In the southern United States, regional slang names like 'mud cat' or 'chucklehead' are used, though these terms vary by location. Catfish hold cultural significance in various regions, with historical records of giant specimens, though scientific verification of extreme sizes is rare.
Status and threats
The order Siluriformes is classified as Least Concern overall due to its vast diversity and wide distribution. However, individual species face threats from habitat destruction, pollution, and overfishing. Large species like the Mekong giant catfish are particularly vulnerable to dam construction and commercial exploitation. Conservation efforts focus on protecting critical freshwater habitats and managing fishing quotas. Data deficiency exists for many lesser-known species, making global population assessments challenging.
Questions people ask about Catfish
Why do catfish have whiskers?
Catfish barbels are sensory organs packed with chemoreceptors. They allow the fish to detect chemicals and taste food in the water, compensating for their generally poor eyesight. This adaptation helps them find prey in dark or muddy environments.
Are all catfish venomous?
Most catfish possess sharp spines on their dorsal and pectoral fins that can cause injury. While many species have glands that produce venom along these spines, not all are toxic. Some stings can be severe enough to require hospitalisation, but lethal cases are rare.
What is the largest catfish species?
The Mekong giant catfish is one of the largest, with recorded weights exceeding 290 kilograms. Other large species include the wels catfish and the piraíba. These giants inhabit major river systems in Asia and Europe respectively.
Do catfish have teeth?
Many catfish species lack incisiform teeth entirely. Instead of biting, they use suction or gulping mechanisms to ingest prey. Some families have modified mouths for attaching to surfaces, but few rely on traditional chewing teeth for feeding.
Good reading and sources
The facts on this page come from the Wikipedia article "Catfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
Like Catfish
All catfishes
Sub-Saharan AfricaSynodontis
A large African genus of spotted catfish known for squeaking sounds and belly-up swimming.Catfish · Rivers and lakes
🇧🇴 Bolivia and 4 moreRipsaw catfish
Large thorny catfish native to South American rivers.Catfish · Rivers and lakes
🇧🇷 Brazil and 4 moreRedtail catfish
A large South American catfish known for its red tail and popularity in the aquarium trade.Catfish · Rivers and lakes
🇧🇷 Brazil and 1 moreAncistrus
A genus of small, nocturnal freshwater catfish native to South America and Panama.Catfish · Rivers and lakes