Predatory fish : Wels Catfish (Silurus glanis)

Wels catfish (Silurus glanis) - Credit 123RF

The wels catfish, also known as Silurus glanis, is the largest predatory fish found in European waters.

It is an impressive freshwater fish with a distinctive appearance and rapid growth. This catfish species has become a prized target for anglers who see it as the ultimate trophy. The Wels catfish belongs to the Siluridae family and is also known as the European catfish or simply Wels.

Wels catfish (Silurus glanis) - Credit Bildspende von Dieter Florian on Wikimedia Commons
Wels catfish (Silurus glanis) – Credit Bildspende von Dieter Florian on Wikimedia Commons

What is a Wels Catfish (Silurus glanis)?

The wels catfish (Silurus glanis) is a large freshwater fish native to the rivers of Eastern Europe. It is a giant fish that can reach lengths of over 2 meters. The wels catfish is the only predator capable of eating a 90 cm salmon.

Description of a Fish: Wels Catfish (Silurus glanis)

Identification of Wels Catfish

The wels catfish is a large freshwater fish that can reach up to 3 meters in length. It belongs to the catfish family. It has a thick and robust body of considerable length, characterized by a bulging front and a laterally compressed posterior part. Its scaleless skin is covered in abundant mucus.

The wels catfish has a massive, flattened head surrounded by six barbels, two of which are very long and located above, and four shorter ones under the chin. It possesses numerous tiny teeth that form a kind of rasp, helping it grasp and hold its food before swallowing it whole.

Its eyes are small, and the dorsal, pectoral, and anal fins are well-developed. The anal fin, which is very long, reaches the small, rounded caudal fin. The upper parts, flanks, and anal fin of this fish are marbled with large brown-black and gray-brown spots on a gray background, while the other fins are darker, almost black.

S. glanis
Binomial Name
Silurus glanis (Linnaeus, 1758)
The binomial name for the Wels Catfish (Silurus glanis), with Linnaeus being credited as the authority who first described it in 1758.

Size, Weight, and Growth

The wels catfish can reach lengths of up to 3 meters and weigh up to 120 kg. Smaller specimens typically measure between 1 and 2 meters. The growth rate of the wels catfish is rapid, often reaching 2 to 3 kg per year during the first few years of its life.

Wels Catfish lifespan

The wels catfish can live up to 80 years in the wild. Females often have a longer lifespan than males.

Habitat and Lifestyle of Wels Catfish


The Wels Catfish (Silurus glanis) is widely distributed in freshwater habitats in Eastern Europe and Asia, including Russia, Ukraine, Moldova, Romania, Hungary, Serbia, Bulgaria, and Greece. It can also be found in the brackish waters of the Danube and Volga deltas.

The wels catfish was introduced to Western Europe in the 1930s and 1940s for sport fishing purposes and to diversify aquatic fauna. Since then, it has spread widely in rivers and lakes throughout Western Europe. However, its impact on native fish populations has been a source of controversy and concern for the conservation of native aquatic fauna.

The wels catfish prefers calm and deep waters with abundant vegetation and structures such as fallen trees or underwater reefs. It is a solitary and territorial fish, defending its living space against intrusions.

Diet of Wels Catfish

The wels catfish is an opportunistic predator that feeds on fish, amphibians, mollusks, crustaceans, birds, small mammals, and even other catfish. It ambushes its prey by lying in wait near underwater structures and surprising them with a sudden acceleration. Although it is capable of hunting prey larger than itself, it prefers injured, sick, or dead fish. The wels catfish occupies the top of the food chain in the freshwater ecosystems where it resides.


The wels catfish reaches sexual maturity at around 4 years of age and typically reproduces between May and July when the water temperature reaches around 20°C. Females deposit their eggs in groups on submerged vegetation and can lay up to 15,000 eggs per kilogram of their body weight. The hatched fry emerge approximately one week later and remain attached to the vegetation for several days, feeding on zooplankton.

Importance of Wels Catfish for Anglers

Gastronomic Importance

The wels catfish is highly valued for its firm and tasty flesh. Many anglers dream of serving freshly caught wels catfish to their guests. However, due to the substantial size of these fish, it is often necessary to share them.

Importance in Fish Farming

The Wels Catfish (Silurus glanis) is an important fish for aquaculture due to its noble qualities and longevity. Catfish farms are often used for the production of table fish, contributing to the growth of the fishing industry.

Role in the Ecosystem

The wels catfish is also used as a natural regulator in ponds and small lakes. It helps control populations of smaller fish, such as whitefish, by preying on them. This helps maintain the balance of the aquatic fauna and preserve biodiversity.

Interest of Wels Catfish for Anglers as a Game fish

For anglers, catching a wels catfish is a formidable challenge. This fish is known for its strength and power, making it a formidable opponent for any angler. Once captured, the wels catfish can provide an unforgettable experience and a trophy-worthy photo. However, it is important to release the fish safely, as it can be dangerous for anglers who are not careful enough.

Fishing Techniques for Wels Catfish

Wels catfish are primarily caught using angling techniques. Lures are often used to attract the fish, while live bait is used to provide a more natural prey. Anglers can also employ techniques such as trolling to capture this formidable predator. Unfortunately, habitat degradation and increasing river channelization can make wels catfish fishing more challenging.

Common names for Wels Catfish

Wels Catfish is also known as European Catfish or Danube Catfish in USA.
Most popular common names for the Wels Catfish are Silure (french), Waller (german), Siluro (italian and spanish), Meerval (dutch) and Sum pospolity (polish).

Conservation Status of Wels Catfish (Silurus glanis)

The conservation status of the wels catfish is classified as LC (Least Concern) according to the IUCN Red List. The “Least Concern” category indicates that the species is widely distributed and abundant, signifying a healthy population.


The wels catfish is a scaleless freshwater fish that can reach up to 2.7 meters in length and weigh up to 130 kg on average. In French waters, the record size is 2.74 meters. It has six sensory barbels and a very short dorsal fin.

Wels catfish (Silurus glanis) can be found in various freshwater habitats across Europe, including rivers, lakes, and reservoirs. They are native to Eastern Europe, particularly in countries such as Russia, Ukraine, Moldova, Romania, Hungary, Serbia, Bulgaria, and Greece. Additionally, wels catfish have been introduced to Western Europe, including France, in the 1930s and 1940s for sport fishing purposes. They have since spread widely and can be found in rivers and lakes throughout Western Europe. They have even adapted to colder temperatures in Alpine lakes. Overall, wels catfish are widely distributed and can be encountered in both river and lake environments.

Wels catfish prey on fish, insects, mollusks, crayfish, amphibians, turtles, birds, mammals, and even smaller catfish.

Wels catfish are solitary omnivores that avoid light and have an average lifespan of twenty years. They primarily feed on fish, crustaceans, and mollusks but can also adapt to their environment and expand their diet by hunting small rodents or young water birds. While they are primarily nocturnal, their activities are temperature-dependent, becoming more active when the water temperature exceeds 15°C.

Their hunting is mainly done in murky waters, where they are sensitive to sounds, electromagnetic fields, and pressure changes from their prey but can also detect chemical signals. Once close enough to their prey, their wide mouth opens rapidly, creating a suction that allows them to swallow the prey whole.

The primary diets of wels catfish consist mainly of fish but also include insects, mollusks, crayfish, amphibians, turtles, birds, mammals, plants, and even mineral matter. They are considered opportunistic feeders and can target substantial prey such as large carp and larger fish like salmon or shad. Wels catfish are also scavengers and are attracted to strongly scented foods, such as lamb ribs, chicken bones, and wild boar skins. They are also capable of cannibalism and feeding on smaller congeners. Unfortunately, they are sometimes attracted to plastic items, which can lead to death by asphyxiation.

Wels catfish are an invasive fish species that pose a threat to migratory fish populations, especially species already in decline and threatened due to overfishing, water pollution, and climate change. They adapt easily and reproduce rapidly, which can lead to the collapse of migratory fish populations. European catfish species have been recognized by scientists as a threat to these species.

Additionally, wels catfish can survive and spread more easily than other fish in warmer waters due to climate change. This means they could expand into previously inaccessible areas and pose a greater threat to native populations and migratory fish.

Finally, they are not classified as a harmful species, although anglers fear their impact on other species. Moreover, wels catfish can accumulate mercury and other pollutants that make them unfit for consumption. This means the future of wels catfish will largely depend on humans’ ability to manage their populations and protect other species.

Wels catfish can live up to 80 years in favorable environments, but their average lifespan is around 20 to 30 years.

Fishing for wels catfish offers numerous benefits, which have made it increasingly popular. Firstly, it can be practiced using different techniques such as lure fishing, float fishing with bait, or even using a float tube or kayak. It can also be pursued year-round, even during colder periods of the year.

The products derived from wels catfish fishing primarily include fillets, but they can also be transformed into steaks, tartare, or smoked fish. Wels catfish are also used to produce oils and protein-rich flours that contain B-group vitamins and minerals. Additionally, wels catfish are used in the production of pharmaceutical products such as nutritional supplements based on their nutrient compounds.

Wels catfish is edible, but its strong flavor and firm texture can be divisive among consumers. Some anglers enjoy its distinctive taste, while others find it less pleasant. Additionally, wels catfish is highly nutritious, being rich in proteins and lipids, and providing a variety of essential B-group vitamins and minerals. Lastly, wels catfish is available in fillet form, making it easy to cook without seeing its head. It is important to note that due to its size and predatory nature, wels catfish can accumulate heavy metals and other pollutants, so it is crucial not to consume them in excess and to cook them thoroughly to avoid any contamination. It is recommended to remove the fatty parts of the fish, where pollutants are most likely to accumulate.

Wels catfish can be consumed, but it is best to avoid consuming those caught in natural environments as they accumulate pollutants and heavy metals from their prey throughout their lives. It is preferable to purchase wels catfish fillets from aquaculture sources if you wish to consume them.

Attacks by wels catfish on humans are extremely rare and only occur in very specific circumstances when the fish feels threatened or provoked. It is important to note that wels catfish are not natural predators of humans, and most wels catfish are harmless. Despite their impressive size and reputation as formidable meat-eaters, these fish do not have teeth strong or sharp enough to seriously harm anyone. In fact, their diet mainly consists of fish, crustaceans, frogs, and other small aquatic animals. Therefore, wels catfish can be safely fished using appropriate techniques and taking necessary precautions to avoid any incidents.

It is highly unlikely for a wels catfish to eat a dog since wels catfish primarily feed on fish and crustaceans. However, if a small or medium-sized dog were to cross paths with a wels catfish while swimming and the catfish was in a hunting mode, it is possible that it could be devoured. Therefore, it is important to supervise young children and pets when they are near the water to prevent any accidents.

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