The largest freshwater fish in Europe is the wels catfish. It can grow to an amazing size of 5 metres in length, although (due to our colder climate) British catfish are much smaller than their continental cousins. They are not a native species to our island, arriving only 100 years or so ago. But they have become the largest freshwater predators we have.
Despite their size, you are unlikely to come across a wels catfish on a stroll by a river or lake. That’s because they like to live in the deepest waters of lakes or slow flowing rivers. They also tend to hide in sunken logs, underwater holes and the like, and are most active during the hours of darkness. But if you do ever see one, you should be able to recognise it at once.
Wels catfish are considered ugly by some. They have long, tapering bodies with short, stumpy tails at the end. At the front is a large, flattish head with six ‘barbules’ (the ‘whiskers’ from which the catfish gets its name). They also have wide mouths packed with a myriad of tiny teeth which they use to kill their prey.
So what do wels catfish eat? Almost anything! There are reports of them eating swimming dogs, though (if true) that would be very rare. They usually feed on small fish, amphibians, young waterfowl or swimming small mammals like rats or mice. They have been known to attack people but, before you panic, this was after being caught by anglers. The animals were defending themselves rather than looking for a meal.
Wels catfish are not very common here in the UK, though the population is spreading. They first arrived in the 19th Century after being introduced to the waters of Woburn Abbey. Some escaped from there but did not spread far. Up until 1990, most wels catfish here lived within 50 miles of the Abbey. Since then however, their numbers have increased. Many have been imported and released into our waters to attract anglers. Now, almost every county has at least one place they can be found.
Do you think it is a good idea to introduce non-native species to our waters? What effect will they have on our natural ecosystems? Let the Education Quizzes team know your thoughts by commenting in the box below.