The wels catfish, aka sheatfish or wels, is a massive species of catfish native to wide areas of Europe and Asia. They’re also found in the basins of the Baltic, Black, and Caspian Seas. Due to the destruction and degradation of natural river networks, via habitat loss and destruction, specifically the loss of large connected floodplains and shallow spawning areas, their reproduction is severely impacted. Populations located in the northern periphery—like those restricted to isolated lakes and rivers in Sweden—exhibit low genetic diversity and fragmentation, raising vulnerability to local extinction. Via centuries of environmental changes and human pressure the species has gone extinct in Denmark in circa 1700s and Finland in circa 1800s. Due to climate change rapid aquatic changes have altered natural water temperatures and seasonal flows, disrupting traditional spawning triggers. However, these catfish are abundant and have a wide distribution, therefore they are listed as Least Concern by the IUCN. Their population trend is listed as stable. This article is dedicated to my friend Stefan.
First the Stats…
Scientific name: Silurus glanis
Weight: Up to 660 lbs.
Length: Up to 9.6 feet
Lifespan: Up to 70 years
Now on to the Facts!
1.) Their English common name hails from Wels, the common name of the species in the German language.
2.) They’ve been around since the late Miocene epoch (5.3 million years ago).
3.) These catfish rely heavily on their sensitive Weberian apparatus and chemoreceptors to locate food in the often murky water.
4.) They, like other catfish, are nocturnal (active at night).
5.) With their elongated body design, wels are capable of swimming backwards like eels.
But wait, there’s more on the wels catfish!
6.) Large individuals are rumored to attack humans in rare instances. This was investigated by extreme angler Jeremy Wade in an episode of the Animal Planet show River Monsters following his capture of 3 fish, 2 of about 145 lbs. and 1 of 164 lbs. 2 attempted to attack him following their release.
7.) Females can produce up to 30,000 eggs per 2.26 lbs. of body weight.
Did you know…?
These fish are the 2nd largest freshwater fish found in Europe and western Asia, after the beluga sturgeon.
8.) Annelid worms, gastropods, insects, crustaceans, fish, crayfish, eels, frogs, snakes, rats, mice, voles, coypu, ducks, and even one another are all on the menu.
9.) Following the introduction of wels catfish, populations of other fish have undergone drastic declines. Since their introduction in the Mequinenza Reservoir in 1974, these catfish have spread to other parts of the Ebro basin, including its tributaries, especially the Segre River.
10.) In June 2025, 1 of these fish were shot at by a police officer after it had bitten 5 people in the Brombachsee in northern Bavaria. The incident attracted media attention and sparked outrage on social media.
Now a Short Wels Catfish Video!
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Some source material acquired from: Wikipedia & IUCN
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