A flat head, small eyes, long barbels, a size of 2 meters long, a weight exceeding 100 kg, this fish with impressive dimensions is none other than the catfish. After having disappeared between the 12th and 18th centuries from the basins of the Rhine, the Meuse and the Escaut, this large “catfish” was reintroduced in the 19th century and spread from the 1970s. It now lives in all the fresh waters of the French territory. Because of its large size and its unflattering appearance, “There are a whole bunch of urban legends surrounding the catfish,” explains Dr. Gaël Denys, Ichthyofauna at the French Office of Biodiversity. “For example, it was said that it could reach a size of 5 meters, which is false. We know that the maximum known size is closer to around 2.80 meters.”he continues. Its frightening characteristics make it a fish feared by many swimmers. Who would want to come across such a beast while swimming?
The catfish is part of what is called the “top predators”, it is at the top of the freshwater food chain in Europe. This means that apart from itself, it has no other predator. It is very opportunistic, it can feed on fish, crayfish, freshwater mussels, coypu, moorhens, or even ducks. Specimens have already been observed leaping out of the water to land on the banks of the Tarn in Albi and seize a pigeon. Cannibalistic habits (large catfish feeding on small catfish) have also been noted in the Rhône and the Garonne. Despite this threatening characteristic, the catfish is not a predator for humans.
Catfish attacks on humans have already occurred, but only in very specific cases. These were people who were walking in the water on shallows and who passed close to the spawning grounds (places where the eggs are found). This animal being very protective of its offspring, the parents who were guarding the nests attacked the swimmers on the legs. “These attacks are very rare, and none have been fatal.”adds Dr. Denys, wanting to be reassuring. If such cases can frighten people bathing in fresh water, “the catfish is not a dangerous fish”he says.
The catfish is a fish that generally lives in schools, it is sedentary and territorial. It stays close to its hole at the bottom of the water and comes out rather at night (it is a light-sighted fish) to hunt. But it is also a curious animal, it happens that one of them approaches a swimmer or a diver. “People working in dam maintenance, for example, may be confronted with a curious catfish that comes to see what’s going on.” If you come across an indiscreet catfish while swimming, don’t panic: “There is no need to be afraid, but we must remember that we are the ones in his environment, we must not bother him.” concludes the specialist.