Wels Catfish Interesting Facts
The Wels catfish, or Silurus Glanis, is one of the largest freshwater fish in the world. This water monster can grow up to 16 feet long and weigh up to 675 lbs. That’s larger then two full grown men! This giant fish is able to grow up to these sizes because they have an average lifespan of 30 years, so that’s 30 years to do nothing but eat and breed. Please note that these large sizes are rare but not unheard of. Most Wels catfish average a size of 4 to 5 feet and weigh in at around 33 to 44 lbs but that is still a pretty big fish!
The Wels catfish has a large mouth with numerous rows of small sharp teeth. They have two large barbels on their upper face and shorter barbels on their lower jaw that resemble whiskers like that of a cat, hence its name.
They also have a long anal fin that extends all the way to the caudal fin. A small sharp dorsal fin can be found closer to the head but you have to really look close. They use their sharp pectoral fins to create an eddy to disorient it’s victims so they can suck in the prey whole.
These catfish live and flourish in deep slow moving rivers and large warm lakes. They prefer to remain in more sheltered locations like holes in the riverbeds or hollowed out sunken trees and in the weeds and vines. These catfish are found more in Europe and western Asia, however they have been introduced into Britain, Italy, Spain and Greece along with a few other countries in the last century.
Some of the more well known areas that you can find Wels catfish are the River Danube, River Po in Italy and River Ebro in Spain. Sadly these fish are also considered an invasive species in some parts of Canada. These fish are sometimes released in rivers and ponds where they are not naturally supposed to be and end up eating every other fish in the pond. They become a top predator and can wreck the local ecosystem.
A strange habitat for these fish exists inside the dangerous Chernobyl exclusion zone. Inside one of the abandoned cooling ponds and channels lives a small population of wels catfish. It’s in close proximity to the decommissioned power plant and while these catfish appear healthy and are maintaining the position of top predator they are also growing into these rare sizes. Some people think it’s due to the nuclear toxins and that these fish are being mutated but scientists believe their greater sizes are due to them having no other competition for food and being the top predator.
Did you know?
The Wels catfish was named twice! Wels is an old German word for Catfish so the name of this giant fish is actually, Catfish Catfish.
Diet and Hunting
What exactly does a giant catfish eat? Well they will eat just about anything they can fit in their mouth. These catfish have been known to devour other fish, frogs, birds and even road kill that people have thrown into the river. These water beasts have also been known to eat small mammals such as small domesticated pets. Yes they have eaten small dogs who have gone out for a swim in the rivers or lakes with their owners. They have even been found to eat sheep whole and practice cannibalism by eating other smaller wels catfish. The smaller sized wels catfish will eat annelid worms, gastropods, insects and small crustaceans.
Wels catfish have been known to lunge out of the water in order to hunt birds such as ducks and pigeons. When breaching the water it was found in a study that the catfish were only successful about 28% of the time. They use a similar hunting technique when going after other fish as well. The catfish will spot a fish such as a carp, swimming near the surface of the water and the catfish will begin to follow. It waits until the timing is right and it moves in. The catfish lunges at the carp with it’s mouth wide open and grips the fish with it’s rows of small teeth. While the catfish can’t chew it’s prey it can swallow it whole. The catfish them swims back to its hidden ambush spot.
Ambushing is another technique it uses to capture food. The catfish will lay at the bottom of the river or lake in wait under a log or in a hollowed out tree. The barbs on it’s face can sense vibrations in the water and help locate prey. The catfish also have eyes that can see in the dark and largely rely on hearing and smell during the day. These catfish will lay in wait until it senses vibrations from it’s prey swimming by. It uses hearing and smell to calculate when it’s prey is close and it will lung from it’s hiding spot with an open mouth and suck in it’s food. Their mouth acts as a vacuum as when it opens it creates a suction or vacuum that it can use to swallow it’s prey whole.
Did you know?
The female Wels catfish can lay up to 500,000 eggs at a time. Most of these babies will be eaten by other predators including other wels catfish.
Breeding and Behaviors
Catfish spawning season is during spring and early summer when the waters are warmer. Male catfish will make a nest out of tree roots and underwater vegetation. The female will lay sticky eggs that are about 3 mm in diameter. She can lay around 30,000 eggs per kilogram of body weight so larger catfish can lay more eggs. The male catfish will guard the nest until the eggs hatch which can take between three to ten days depending on the waters temperature. It’s been observed that if the water around the nest decreases too much or too fast, the male will use his massive tail to splash water on the eggs to keep them wet.
After the baby fish, known as fry, hatch the male will stay with them until they are large enough to fend for themselves. Usually only about 10% of the fry will survive. Depending on where the fish live, they can grow fast or slow. In some areas, catfish can grow just 1 to 2 lbs a year while some will grow 3 to 4 lbs a year. Some fish can even grow upwards to 10 lbs or more per year. Generally the growth rates are quicker the warmer the water is so in areas where the water is cooler over the year they don’t tend to grow as fast.