Wels catfish
A large freshwater catfish native to Europe and Western Asia, known for its size and bottom-feeding habits.
The wels catfish is a massive species of catfish native to central, southern, and eastern Europe. It has been introduced to other regions as a sport fish and can grow over two metres long, making it one of the largest freshwater fish in its range.
- Maximum recorded length is 2.92 metres from Poland.
- Lives up to 70 years in cold Scandinavian waters.
- Males guard nests and splash eggs if water drops.
- Introduced to Brazil, surviving floods and establishing populations.
- Diet includes terrestrial birds in introduced French rivers.
What it is
The wels catfish is a heavy-bodied freshwater fish with a flattened head and a long anal fin that reaches the tail. It possesses two long barbels on the upper jaw and four shorter ones below. The skin is slimy and varies from black in clear water to green-brown in muddy conditions, with a pale yellow or white belly. It lacks scales but has sharp pectoral spines. Adults typically measure between 1.3 and 1.6 metres, though specimens over two metres are rare. The species is capable of swimming backwards due to its elongated shape.
Where it lives
Native to basins of the Baltic, Black, and Caspian Seas across central, southern, and eastern Europe. Its range extends from the United Kingdom to western China. It inhabits large warm lakes and deep, slow-moving rivers, preferring sheltered spots like riverbed holes or sunken trees. Introduced populations exist in Western Europe, the Mediterranean, and parts of Asia. In Sweden, it persists only in isolated lakes and rivers, having declined significantly in northern areas.
How it lives
This nocturnal predator relies on hearing and smell, using a sensitive Weberian apparatus to hunt. It creates eddies with its pectoral fins to disorient prey before sucking it into its mouth. Diet includes worms, insects, crustaceans, fish, frogs, snakes, rats, and occasionally birds or small mammals. Larger individuals may cannibalise other catfish. They are opportunistic feeders, sometimes surfacing to eat dead clams or lunging for pigeons near water edges in introduced ranges.
Breeding and life cycle
Females produce up to 30,000 eggs per kilogram of body weight. Males guard the nest until hatching, which takes three to ten days depending on temperature. If water levels drop, males splash eggs with their tails to keep them moist. Young fish grow rapidly in warm climates, reaching maturity faster than those in colder regions where metabolism slows but lifespan extends significantly.
Fish and people
Valued as a sport fish due to its strength and size, often targeted with lures like the clonk. Historically eaten when young, larger specimens are fatty and may accumulate toxins, making them less suitable for consumption. The species appears in folklore and media, including documentaries investigating potential attacks on humans. While generally not dangerous to adults, aggressive behaviour towards handlers has been documented.
Status and threats
Globally not endangered, but local populations face threats. Swedish stocks are Near Threatened due to low genetic diversity and isolation. Historical declines occurred in Denmark and Finland. Introduced populations cause ecological issues, such as declining endemic fish species in the Ebro basin. Conservation efforts focus on protecting isolated native groups and managing invasive impacts in non-native waters.
Questions people ask about Wels catfish
How big does a wels catfish get?
Adults commonly reach 1.3 to 1.6 metres. Rare specimens exceed two metres, with authenticated records reaching 2.92 metres and weighing nearly 135 kilograms. Unverified historical reports suggest even larger sizes.
Is the wels catfish dangerous to humans?
It is not considered dangerous to adults. Documented incidents involve smaller fish attempting to bite handlers or dragging fishermen underwater. Experts conclude they cannot consume adult humans but might swallow children.
What does a wels catfish eat?
It feeds on worms, insects, crustaceans, fish, frogs, snakes, rats, and birds. In introduced environments, they have been observed hunting pigeons and eating dead clams at the water surface.
Where is the wels catfish native?
It is native to central, southern, and eastern Europe, including the Baltic, Black, and Caspian Sea basins. It has since been introduced to Western Europe, the Mediterranean, and parts of Asia and South America.
Can you eat a wels catfish?
Younger fish under 15 kilograms are palatable. Larger specimens are very fatty and may contain high levels of environmental toxins due to their position at the top of the food chain, so they are rarely eaten.
Good reading and sources
The facts on this page come from the Wikipedia article "Wels 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.
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