It has been introduced to Western Europe as a prized sport fish and is now found from the United Kingdom east to Kazakhstan and China and south to Greece and Turkey.

[citation needed] The wels catfish is a long-lived species, with a specimen of 70 years old having been captured during a recent study in Sweden.

[3] The wels is the largest freshwater fish in Europe and Western Asia, only exceeded by the anadromous Atlantic and beluga sturgeon.

Examples include the record wels catfish of Kiebingen (near Rottenburg, Germany), which was 2.49 m (8 ft 2 in) long and weighed 89 kg (196 lb).

A report in the Austrian newspaper Der Standard on 5 August 2009, mentions a wels catfish dragging a fisherman near Győr, Hungary, under water by his right leg after he attempted to grab the fish in a hold.

[17] Like most freshwater bottom feeders, the wels catfish lives on annelid worms, gastropods, insects, crustaceans and fish.

Larger specimens have also been observed to eat frogs, snakes, rats, voles, coypu and aquatic birds such as ducks, even cannibalising on other catfish.

Stable isotope analyses of catfish stomach contents using carbon-13 and nitrogen-15 revealed a highly variable dietary composition of terrestrial birds.

An unusual habitat for the species exists inside the Chernobyl exclusion zone, where a small population lives in abandoned cooling ponds and channels at a close distance to the decommissioned power plant.

Some endemic species of Iberian barbels, genus Barbus in the Cyprinidae that were once abundant, especially in the Ebro river, have disappeared due to competition with and predation by wels catfish.

In 2006, a specimen weighing 86 kg (189.5 lbs) and 1.85 m (6 ft) long was captured in Blumenau, suggesting the catfish have survived and possibly be reproducing.

Although Silurus glanis is not considered globally endangered, the conservation status varies across the species native distribution range.

Larger than this size, the fish is highly fatty and additionally can be loaded with toxic contaminants through bioaccumulation due to its position at the top of the food chain.

[citation needed] Wels catfish can be provoked to bite a lure by the sound of a piece of wood plunging into the water, the clonk.

Host Jeremy Wade concluded that Wels catfish in the area were not large enough to consume adult human beings, but could easily swallow a child.