It weighs the same as a gorilla, can reach 3m long and has a huge mouth packed with rasping teeth – and it’s been biting swimmers

In June 2025 there was a series of attacks on swimmers in Bavaria, Germany. Five people were bitten by a 2-metre-long wels catfish while swimming in Brombachsee, a reservoir near Pleinfeld, before the culprit was caught.

The following month, another incident occurred near Absberg, prompting further police action and the removal of rafts that were used for swimming.

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It was believed that the catfish were acting in defence and protecting territory rather than regarding people as prey, but when freshwater fish grow as large as the wels, almost anything is on the menu.

Native to central-eastern Europe and western Asia, the wels is among the largest freshwater fish in the world. Anglers have caught specimens weighing 135kg and measuring almost 3 metres long, and there are reports of individuals considerably bigger.

They have wide heads and long, tapered bodies, and are often likened in appearance to a giant, whiskered slug. The vast mouth is lined with multiple rows of small, rasping teeth, and wels are happy to scavenge as well as hunt live prey.

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Remains of wild boar and deer have been recovered from the bodies of wels, although tales of human body parts being found are unsubstantiated. Wels are long-lived, reaching 70-years-old or more, and are causing issue in areas of western Europe where they have been introduced.

Stocked into waterways in France, Spain, Italy, the Low Countries and the UK, primarily for their sporting qualities, wels have had a significant impact on some ecosystems. Perhaps the most documented case is from a population that has spread through much of the Ebro basin following a 1974 release into the Mequinenza Reservoir. Endemic species such as the Iberian barbel (Luciobarbus comizo) have suffered huge decline in areas where they were once abundant. 

It’s probably sensible not to swim there, either….      

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