Wels catfish facts for kids
Quick facts for kids Wels catfish |
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| Near Leipzig, Germany | |
| Conservation status | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Siluridae |
| Genus: | Silurus |
| Species: |
S. glanis
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| Binomial name | |
| Silurus glanis Linnaeus, 1758
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| Range of the wels catfish. Red: native occurrence. Blue: occurrence in coastal waters. Orange: (re)introduced | |
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The wels catfish (Silurus glanis), also known as sheatfish or just wels, is a very large type of catfish. It lives naturally in many parts of central, southern, and eastern Europe. You can find it in rivers and lakes that flow into the Baltic Sea, Black Sea, and Caspian Sea. People have also introduced this fish to other countries in Western Europe, the Mediterranean basin, and Asia. It is a popular sport fish. Today, its home range stretches from the United Kingdom all the way to western China.
Contents
Discover the Wels Catfish
What's in a Name?
The English name "wels catfish" comes from the German word Wels. This word is very old. It comes from an even older word that also gave us the word "whale". This shows how people have long seen this fish as a giant of the waters, much like a whale!
A Journey Through Time: Wels Catfish Evolution
Scientists have found the oldest known fossils of the wels catfish in Ukraine. These fossils are about 5.3 million years old. Even older, but less clear, fossils from 6-7 million years ago have also been found there. Back then, a different type of catfish, called Soldatov's catfish, was more common in eastern Europe. It liked warmer weather.
Over millions of years, the Earth's climate changed, becoming cooler and drier. The wels catfish was better at adapting to these changes. It slowly became more widespread. Eventually, it replaced Soldatov's catfish in the region. This shows how animals can adapt and thrive as their environment changes over long periods.
Meet the Wels Catfish: Appearance and Senses
The wels catfish has a wide mouth filled with many small teeth. It has two long whiskers, called barbels, on its upper jaw. It also has four shorter barbels on its lower jaw. These barbels help it feel and taste its surroundings. The fish has a long fin on its underside, called the anal fin, which reaches almost to its tail. It also has a small, sharp fin on its back, called the dorsal fin, located closer to its head.
This fish relies a lot on its amazing hearing and smell to find food. It has special body parts that make its hearing very sensitive. Its eyes also have a special layer, like a mirror, that helps it see better at night. This is when the wels catfish is most active. When hunting, it uses its strong pectoral fins to create swirling water. This can confuse its prey, which the catfish then sucks into its mouth and swallows whole.
The wels catfish has very slimy skin. Its skin color can change depending on where it lives. In clear water, it might look black. In muddy water, it often appears greenish-brown. Its belly is always a pale yellow or white. Sometimes, you can even find rare albino wels catfish, which are completely white. Wels catfish have long, eel-like bodies. This shape allows them to swim backward, just like an eel!
How Wels Catfish Reproduce
A female wels catfish can lay many eggs, up to 30,000 for every kilogram of her body weight. The male catfish is a protective parent. He guards the nest of eggs until they hatch. This usually takes about three to ten days, depending on how warm the water is. If the water level drops too much, the male has been seen splashing water onto the eggs with his tail. This keeps them wet and helps them survive.
Wels catfish can live for a long time. Scientists recently found a wels catfish in Sweden that was 70 years old!
How Big Can They Get?
The wels is one of the biggest freshwater fish in Europe and Western Asia. Only some types of sturgeon, which travel between fresh and saltwater, can grow larger. Most adult wels catfish are about 1.3 to 1.6 meters (4 to 5 feet) long. Fish longer than 2 meters (6.5 feet) are quite rare. A wels catfish that is 1.5 meters (5 feet) long can weigh between 15 and 20 kilograms (33-44 pounds). A 2.2-meter (7.2-foot) fish can weigh around 65 kilograms (143 pounds).
Sometimes, in perfect conditions, wels catfish can grow even bigger than 2 meters. For example, a record wels catfish caught in Germany was 2.49 meters (8.2 feet) long and weighed 89 kilograms (196 pounds). Even larger ones have been caught in places like Poland, the Czech Republic, Ukraine, Russia, Kazakhstan, France, Spain, Italy, Serbia, and Greece. The mild climate and good food supply in Greece have helped these fish grow very well.
The heaviest wels catfish ever officially recorded was caught in Italy's Po River in 2010. It weighed 134.97 kilograms (297.56 pounds). The longest wels catfish on record was also from the Po River, caught in 2023, measuring 2.85 meters (9.35 feet).
It's possible that some wels catfish might grow to be over 3 meters (10 feet) long and weigh more than 200 kilograms (440 pounds). Such huge sizes are very rare today. However, there are some old reports from the 19th century that mention wels catfish of this incredible size. For instance, reports from the Danube River talked about fish 3 meters long and weighing 200-250 kilograms.
What Do Wels Catfish Eat?
Like many fish that live near the bottom of freshwater, the wels catfish eats a variety of things. Its diet includes worms, snails, insects, small crustaceans, and other fish. Larger wels catfish have also been seen eating crayfish, eels, frogs, snakes, rats, voles, and even aquatic birds like ducks. They might even eat smaller wels catfish!
Scientists in France observed wels catfish in a new environment. These fish learned to lunge out of the water to catch pigeons near the water's edge. This amazing behavior was filmed, and about 28% of these attempts were successful. This shows how adaptable wels catfish can be when they move to new places and find new food sources. This behavior was not seen in their native homes. They can also eat red worms, especially in the fall.
Wels catfish have also been seen taking advantage of large numbers of dead Asian clams. They feed on these clams floating on the water's surface during the daytime. This shows they are smart and can find food in different ways, even though they usually feed at night near the bottom.
Where Do Wels Catfish Live?
The wels catfish prefers to live in large, warm lakes and deep rivers where the water flows slowly. It likes to hide in sheltered spots, such as holes in the riverbed or around sunken trees. It usually finds its food in open water or in deeper areas. People also raise wels catfish in fish ponds to be used as food fish.
An interesting place where wels catfish live is in the Chernobyl exclusion zone. A small group of these fish lives in the abandoned cooling ponds and channels near the old power plant. These catfish appear healthy and are important top predators in that area's water ecosystem.
Wels Catfish in New Homes
When wels catfish are introduced to places where they don't naturally live, there can be concerns about their impact on the environment. In some areas, after wels catfish arrived, the populations of other fish species have decreased a lot. For example, in Spain's Ebro River basin, some native fish that used to be common have disappeared. This is because the wels catfish competes with them for food and also eats them. The river's environment has also changed, with more aquatic plants like algae growing.
Wels catfish might have also started living in Santa Catarina, Brazil. Some were brought from Hungary in 1988. A flood caused their tanks to overflow, washing them into the Itajaí-Açu river. In 2006, a large wels catfish weighing 86 kilograms (190 pounds) and measuring 1.85 meters (6 feet) was caught there. This suggests the fish have survived and might be having babies in Brazil.
Protecting Wels Catfish Populations
Even though the wels catfish is not considered endangered worldwide, its situation varies in different places. In the northern parts of its natural range, like Denmark and Finland, the species disappeared centuries ago. In Sweden, it now lives in only a few lakes and rivers and is considered "near threatened." Recent studies show that the Swedish populations have low genetic diversity and are isolated from each other. This means they need special care to protect them.
Wels Catfish and People
Younger wels catfish are generally considered good to eat. Their meat tastes best when the fish weighs less than 15 kilograms (33 pounds). Larger fish tend to be very fatty. Also, because they are at the top of the food chain, very large wels catfish can collect harmful substances in their bodies. So, eating very large specimens is not recommended. However, big wels catfish are popular with sport fishers because they put up a strong fight. A special fishing lure called a "clonk" is often used to attract them. It makes a unique sound in the water that makes them bite.
Safety Around Large Wels Catfish
Very large wels catfish are powerful creatures. While they usually eat smaller prey, their size and strength mean they could pose a risk to small children or pets if encountered in the water.
In April 2009, a fisherman in Hungary reported a large catfish pulling on his leg after he tried to grab it. He managed to get away, estimating the fish weighed over 100 kilograms (220 pounds).
The TV show River Monsters featured the wels catfish. The host, Jeremy Wade, found that while the fish he caught were not big enough to eat an adult human, they were very powerful. He observed that some large wels catfish showed aggressive behavior towards him after being caught.
In June 2025, a large wels catfish in Germany's Brombachsee lake caused concern for swimmers. Local authorities decided to remove the fish for public safety. After the fish was removed, an animal rights group announced plans to question the decision, citing nature conservation laws.
Other Catfish Relatives
- Aristotle's catfish (Silurus aristotelis) from Greece. This is the only other catfish species native to Europe, besides the wels catfish.
- Amur catfish (Silurus asotus), which has been introduced to some European rivers.
- Giant Lake Biwa catfish (Silurus biwaensis) from Japan, found only in Lake Biwa.
- Soldatov's catfish (Silurus soldatovi) from the Amur River in Russia.
See also
In Spanish: Siluro europeo para niños
 | John T. Biggers |
 | Thomas Blackshear |
 | Mark Bradford |
 | Beverly Buchanan |
