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Friday, 16 March 2012

Man-Eating Wels Catfishes and Others

I had a request to put up some information about man-eating Wels catfish. However,  this blog posting on the subject was accumulating errors because of sluggish Bloggo service and had to be taken down. I apologise if that part inconvenienced anybody.
The primary recent source  thatsubject these days comes from the cable TV series River Monsters:


Silurus glanis

wels catfish

Maximum Length: Up to 10 feet
Maximum Weight: Up to 330 pounds
Vicious and Voracious: The wels catfish is defined by a long, scaleless body; a broad, flat head; and an extremely wide mouth containing rows of small, sandpaper-like teeth — hundreds of them. It also has two sets of barbels (whisker-like organs) on the upper and lower jaw, which help the fish hunt its prey in the murky waters of large lakes and slow-flowing rivers across Europe. The wels catfish is an adept hunter, first using its pectoral fins to create a disorienting eddy and then taking advantage of its vast, vacuum-like mouth to suck prey in and swallow it whole.
Maneater or Misunderstood? Tales of man-eating wels catfish date back as far as the 15th century, but 2008 saw a spate of attacks in Lake Schlachtensee outside of Berlin. Many believe the attacker to be a 5-foot wels catfish. These fish have been caught in Russia with human remains in their stomachs, but most experts suspect the victims were already drowned before being swallowed. Still, the wels catfish can exhibit aggressive behavior during its mating season, making it plausible that this monster fish could be responsible for attacks against humans that venture into its territory.
catching wels catfish Jeremy Wade's Tips for Catching Wels Catfish: "Because the water level has been raised by the dams, there are lots of sunken snags, so allowing the fish to run is not an option. But nobody's told the catfish that, and this one charged out into the current and almost pulled me over. It's then a long, drawn-out tug o' war, digging my heels into the slippery bank..."
For the full story, click on the fish icon over Europe on our River Monsters Map.
The wels catfish is an adept hunter, first using its pectoral fins to create a disorienting eddy and then taking advantage of its vast, vacuum-like mouth to suck prey in and swallow it whole

The wels catfish made headlines in 2008 after a spate of attacks in Lake Schlachtensee outside of Berlin.

Wels catfish
From Wikipedia, the free encyclopedia
The wels catfish (play /ˈwɛls/ or /ˈvɛls/;[1] Silurus glanis), also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth. Wels catfish can live for at least thirty years and have very good hearing.
The wels catfish lives on annelid worms, gastropods, insects, crustaceans, and fish including other wels catfishes; the larger ones also eat frogs, mice, rats and aquatic birds such as ducks.

The wels catfish lives in large, warm lakes and deep, slow-flowing rivers. It prefers to remain in sheltered locations such as holes in the riverbed, sunken trees, etc. It consumes its food in the open water or on the bottom, where it can be recognized by its large mouth. Wels catfish are kept in fish ponds as food fish.

Physical characteristics

Wels catfish's mouth contains lines of numerous small teeth, two long barbels on the upper jaw and four shorter barbels on the lower jaw. It has a long anal fin that extends to the caudal fin, and a small sharp dorsal fin positioned relatively far forward. It uses its sharp pectoral fins to capture prey. With these fins, it creates an eddy to disorient its victim, which it then simply engulfs in its enormous throat. It has very slippery green-brown skin. Its belly is pale yellow or white. Colour varies with environment. Clear water will give the fish a black coloration while muddy water will often tend to produce brownish specimens. Weight and length are not correlated linearly, and also depend on the season.
The female produces up to 30,000 eggs per kilogram of body weight. The male guards the nest until the brood hatches, which, depending on water temperature, can take from three to ten days. If the water level decreases too much or too fast the male has been observed to splash the eggs with the muscular tail in order to keep them wet.[citation needed]


Silurus glanis. Syr Darya River in Kazakhstan, Baikonur area.
With a possible total length up to 3 m (9.8 ft) and a maximum weight of over 150 kg (330 lb) it is the second largest freshwater fish in its region after the beluga sturgeon. However, such lengths are extremely rare and could not be proved during the last century, but there is a somewhat credible report from the 19th century of a wels catfish of this size. Brehms Tierleben cites Heckl's and Kner's old reports from Danube about specimens 3 m (9.8 ft) long and 200–250 kg (440–550 lb) heavy, and Vogt's 1894 report of a specimen caught in Lake Biel which was 2.2 m (7 ft 3 in) long and weighed 68 kg (150 lb).[2] In 1856, K. T. Kessler[3] wrote about specimens from Dniepr which were over 5 m (16 ft) long and weighed up to 400 kg (880 lb). "The largest authenticated wels, taken from the river Dnieper in the Ukraine in the southern U.S.S.R., measured over 16 ft (5 m) in length and weighed 675 lb (306 kg); elsewhere in Europe and in England, however, the wels seldom exceeds 5 ft (152 cm) in length and 25 lb (I 1 kg) in weight"

Most wels catfish are only about 1.3–1.6 m (4 ft 3 in–5 ft 3 in) long; fish longer than 2 m (6 ft 7 in) are normally extremely rare. At 1.5 m (4 ft 11 in) they can weigh 15–20 kilograms (33–44 lb) and at 2.2 m (7 ft 3 in) they can weigh 65 kilograms (140 lb).
Only under exceptionally good living circumstances can the wels catfish reach lengths of more than 2 m (6 ft 7 in), as with the record wels catfish of Kiebingen (near Rottenburg, Germany), which was 2.49 m (8 ft 2 in) long and weighed 89 kilograms (200 lb). This giant was surpassed by some even larger specimens from Poland, Ukraine, France, Spain (in the River Ebro), Italy (in the River Po and River Arno), and Greece, where this fish was released a few decades ago. Greek wels grow well thanks to the mild climate, lack of competition, and good food supply. The largest accurate weight was 144 kg (320 lb) for a 2.78 m (9 ft 1 in) long specimen from the Po Delta in Italy.[4] Other reports of larger wels (around 5 m (16 ft) or more) are unlikely and are often regarded as typical big fish stories or in some cases misidentifications of the now rare sturgeon.
Exceptionally large specimens are rumored to attack humans in rare instances, a claim investigated by extreme angler Jeremy Wade in an episode of the Animal Planet television series River Monsters. A report in the Austrian newspaper Der Standard on August 5, 2009, mentions a wels catfish dragging a fisherman near Győr, Hungary, under water by his right leg after the man attempted to grab the fish in a hold. The man barely escaped with his life from the fish, which must have weighed over 100 kg (220 lb), according to the fisherman.[5]


There are concerns about the ecological impact of introducing the wels catfish to non-native regions. These concerns take into account the situation in Lake Victoria in Africa, where Nile perch (available in stores as Lake Victoria perch) were introduced and rapidly caused the extinction of numerous indigenous species. This severely impacted the entire lake, destroying much of the original ecosystem. The introduction of foreign species is almost always a burden on the affected ecosystem. Following the introduction of Wels catfish are fishes whose number is in clear and rapid decline. Since its introduction in the reservoir Mequinenza in 1974 - has spread to other parts of the Ebro basin over Ebro and its tributaries, especially river Segre. Some endemics species of iberian barbels, genus Barbus in the Cyprinidae, having once been abundant especially in the Ebro river, competition and predation by wels catfish has caused its complete disappearance in the middle channel Ebro around 1990. The ecology of the river also, has now a major development in the amount of aquatic vegetation, seaweed and algae. Barbel species from mountain stream tributary of the Ebro that wels catfish has not colonized, were not affected.

As a food fish

Only the flesh of young Silurus glanis specimens is valued as food. It is palatable when the catfish weighs less than 15 kg (33 lb). Larger than this size, the fish is highly fatty and not recommended for consumption. The eggs are poisonous and should not be consumed.

Related species


  1. ^ OED
  2. ^ Brehm, Alfred; Brehms Tierleben II - Fish, Amphibians, Reptiles 1
  3. ^ Mareš, Jaroslav; Legendární příšery a skutečná zvířata, Prague, 1993
  4. ^ Wood, The Guinness Book of Animal Facts and Feats, Sterling Pub Co Inc (1983), ISBN 978-0851122359
  5. ^ Der Standard, 2009-08-05. Waller-Wrestling im ungarischen Fischerteich. Retrieved 2009-08-06. (German)
External links

  • FishBase species summary
  • YouTube video of a giant Wels Catfish being caught
  • This article includes information translated out of the German and French Wikipedias.
    --So basically the answer seems to be, when the wels catfish gets big enough and there are human beings present in the water, the catfish is as likely to go after them as any other prey. Catfishes are very indiscriminate feeders. The thing is, they habve to be allowed to get that big, and few of them get that big in Europe any more (larger ones may be commoner in Central Asia these days). Lucas writes wondering if introduced wels catfishres might be mistaken for giant eels: and my answer is that my experience has been that usually witnesses make the distinction. There are some very eel-like catfishes, byt the wels has a fat body that is vaguely tadpole-shaped overall. ntroduced wels might make perfectly acceptable water monsters, my feeling is that ordinarily witnesses make the distintion between them and the eels.
    Best Wishes, Dale D.


    1. I think it is extremely unlikely that a wels has ever killed and eaten a human. They have to swallow their prey items whole, but even at their maximum size, they could hardly swallow a small child. Some years ago I had the chance to see a 2,47 m taxidermy specimen, but even this monster´s mouth was hardly large enouh to eat a baby. Some years ago a wels was found floating dead on the surface, as it had attacked a floating soccer ball, which became stuck in its mouth and the poor fish suffocated. It was not even a real soccer ball like the ones used for professional games, but a smaller one made from rubber. Even at the upper maximum size of around 3 m, a wels could probably only swallow a baby or a very young child.
      Even the gigantic record wels with a total length of 2,78 m and a weight of 144 kg had only a mouth of 34 cm width.
      You can see very good photos of both specimens I mentioned at this site:

      Both photos are especially good, because there is no forced perspective as in most other photos which show anglers with fish, and there is also a size comparison with humans.
      A length of 2,5 m or more SEEMS long enough to swallow a human, but besides the problem of the mouth width, there´s also the body capacity. Most of a wels´ length consists of its tail, the actual "body" is much shorter, and with it the stomach as well. You can see it very well on the photos, as the abdominal region is only around a third of the total length. It´s already hard to imagine a child in a wels, but it´s impossible for an adult. The teeth of a wels are tiny and can scratch skin if anything, but they can´t bite parts off from anything like a shark can.
      Yet I don´t fully deny the possibility of human body parts found in the stomach of wels catfish. It´s highly probable at least some of those stories are just horror stories, but there is no reason to think that a wels would not eat human body parts which it could swallow whole. It´s well known that wels will not only eat whole smaller mammals and birds, but also pieces of meat or intestines, and sometimes fishermen actually use intestines as bait for wels angling.
      As a wels is not able to bite off pieces of a human, I strongly suppose that human body parts which were found in wels stomaches were those of people which were either killed and hacked to pieces by murderers or which became torn by accidents. The second possibility would be that a wels really managed to pull off pieces of dead humans which were already long enough underwater to decay and soften. However I am not sure if even a wels would still feed on a carcass at this stage of decomposition, but I would not rule out this possibility completely.
      Of course the possibility remains that anytime a giant wels really attacked and swallowed a small child, but I think it makes very little sense to declare wels as man-eaters as it was the case at River-Monsters. There are a lot of cases in which humans were eaten by dogs, but are dogs man-eaters in general?

    2. I would tend to agree with you that wels catfishes can probably only scavenge human remains and thus are not truly man-eaters. But very few animals (individuals mostly) are actually career man-eaters, while the vast majority of creatures that can eat human flesh do so only by way of scavenging. Some dogs I would allow were man-eaters, but I would not go about saying that all stray dogs are to be called such. However an alarming number of dogs are quite willing to kill small children. Wolves ordinarily will not kill and eat human beings, but the emphasis is on "ordinarily"

    3. As to the maximum size the Wels catfish can attain in good conditions and without the pressure from humans, a gigantic specimen could still be a good deal larger than the average at what would be considered an abnormally large individual, well above the usual size of the more conventional limits of the species. Some of the data from American catfishes suggest that exceptional individuals under such environmental factors as hormone pollutants in the water and lack of competition, can regularly grow to twice the expected regular maximum sizes. The area is poorly studied since we are talking about exceptional individuals after all. And the biggest ones are also proportionately very much fatter and thicker in proportion than the common catfishes of the same species. However, I don't know if the same phenomenon occurs in the European wels and so the matter remains speculative.

      Best Wishes, Dale D.

    4. If we look at the average, we can see that most wels catfish are not bigger than 1,5 m. Here in central Europe, even specimens of lesser than 2 m often get local media attention, because they are exceptional. I looked really a lot on record specimens of Silurus glanis over the years, and there is a very obvious trend towards a "pyramid"-structure of sizes. There are countless very large specimens over 2 m which were, but for every additional 10 cm, you get lesser recorded specimens. There is still a comparably (i.e. at least several dozen) large number of specimens around 2,5 m, but at only 10 cm longer, there are much lesser specimens. If you look at 2,7 m there is only a handful of really recorded specimens.
      That means the chance there are or were ever any specimens significantly longer than this, is extremely low.
      Those specimens which really reached extreme sizes, were often living in areas with very good conditions. For this reason the number of very large recorded specimens has significiantly increased in recent decades, as they were introduced to many areas. The most famous wels-angling area is the Po-Delta at Italy. This huge delta has perfect conditions for wels, warm temperatures and a lot of food fish. Furthermore wels are there now already since nearly 100 years, and some of the fish there had really a whole lot of time to grow. Furthermore the population there is very high, so the chance to find extremely well growing specimens with very good genetic conditions for massive growth is quite good. Many of the largest ever recorded wels catfish actually come from this area, but even there the really monster-sized specimens of more than 2,6 m are highly exceptional. A wels of 2,78 m is already an abnormally large one, around 50% longer than the average (or more). As weight grows with the cube, they are not just only 50% heavier, but around 300%. I took countless dates of length and weight of confirmed record wels to get an idea about their proportions, including specimens which were unusually thin or fat. There is also a tendency of wels to become fatter with age, and they easier gain additional kg than cm. The first ones which were introduced had the best conditions, as they had least intraspecific competition for food.
      I searched for years for the largest confirmed wels specimens, but I could find none which even touched the 300 cm with certainty. I found a photo of one single specimen which was said to have slightly exceeded 3 m, but it´s hard to jugde from the photo, as it´s not fully visible, and after all it also doesn´t really look bigger than the 2,78 m specimen from Italy. I think the maximum biological size (i.e. without growth hormones or something like that) is probably a little bit over 3 m, and the maximum weight perhaps around 170 kg or so, perhaps more for extremely fat specimens. That´s gigantic if you keep in mind that a wels of 2 m and 65 kg is already very large.
      I know no case in which hormones did lead to a strong growth of fish in the wild, can you give me any additional data?

    5. Thank you very much Markus, you put that into a good perspective. 3 meters may be a good maximum and I did not actually have a firm figure in mind when I brought the subject up. The Wels seems to be only in the same size range as medium-large American catfishes and not the largest ones, and the Lake Biwa catfish at about the same size. As to the matter of hormones: that was stated on a TV nature show and hormones getting into the water were blamed for the problem in the narration, but I did not look into any documentation on the subject. I can try to look it up.

      Best Wishes, Dale D.

    6. There are a lot of large and even very large catfish species all over the world, but many of them are nearly unknown to most people. I am highly interested in fish since my early childhood, but still some of those giant catfish species are so cryptic in literature, that I discovered them lesser than a year ago. It is really a big problem that there is way too much wrong data in literature about sizes of better-known species, and it´s sometimes even worse with the little known species. For example Joseph Nelson´s quite famous and highly authoritative book "Fishes of the World" states for Silurus glanis "commonly reaches 3 m in length". Now that´s really a bad thing, because this is a quite important literal source for many authors.
      Among all catfish the wels is really among the largest ones and can easily dwarf the american catfish. It´s especially much longer than nearly all other catfish. However there are some species which reach similar or even higher weights. Most famous are the giant asian Pangasius sanitwongsei and Pangasianodon gigas. Both reach similar maximum lengths as Silurus glanis, but as they are quite stocky, up to around 300 kg. The giant south american Piraiba Brachyplatisoma filamentosum can also reach lengths of more than 2,5 m, but only a year ago a specimen of slightly over 200 kg was caught, so this species surpasses Silurus glanis in weight. Of course it is quite problematic to compare the sizes, as those fish have quite different proportions, and of course we can never say exactly to the cm where the actual maximum size is. There is also the giant indian goonch, which is however not as long as the piraiba or as heavy as the wels.
      There are some other large catfish like the south american sharptooth catfish, the asian wallagos and of course the north american blue and flathead catfish, which have all similar maximum sizes. The lake Biwa catfish is a quite close relative to Silurus glanis, and there are actually a whole lot of Silurus species between eastern Europe and Northern Asia, which are all quite similar, but most are of quite moderate size. There are some claims about massive sizes for Silurus biwaensis, but reality seems to be once again different. You can read it reaches 270 cm and 150 kg, and there is a photo which seems to show a specimen of this size. However this is not a taxidermy specimen at all, but only a model displayed at Lake Biwa museum, and is only based on anecdotal data. This size would be already quite exceptional for a wels, but lake biwa catfish are in general that much smaller than Silurus glanis, that it is nearly impossible one of them came ever close to this size. Fishbase gives a maximum reported length of 118 cm and 17,8 kg in weight, and I was not able to find any photos of bigger specimens. 2,7 m seems out of range for this species. Even the official homepage of the Lake Biwa museum states only a length of 1,2 m for this catfish.
      I have doubts about the hormones leading to such massive size differences. I looked a lot for experiments with growth hormones and fish, but there was never ever something like a doubling of known maximum sizes. I strongly suppose this states in TV were just highly exagerated.

    7. At one point I was going to run a blog entry on the "Giant" catfish of Lake Biwa and then I found that none of the data really supported the idea of a large size for them either. One interesting fact is that the island of Japan is supposed to rest upon a giant catfish in Folklore, and its wiggling causes earthquakes. There is a similar legend in Siberia but it features a giant sturgeon instead.

      In Cryptozoological circles, Bernard Heuvelmans supported the idea that some Cryptids in Central Africa and South America were truly enormous catfishes but called "Serpents" in the legends. The one in South America he stated was 18 feet (six meters) in length! These statements were so far outside the norm for other catfishes that theyyy always sounded fantastic to me. I am willing to allow for gigantic catfishes as Cryptids in both areas, but in these cases I think the categories that Heuvelmans cites-the Laus and the Mysterious Beasts actually ARE refereces to mythological snakes and not giant catfishes in the first place.

      Best Wishs, Dale D.

    8. Yes, I remember those giant catfish from "In Search of Hidden Animals". It is strange that there are so few real megafish on the african contitent, except of course the huge nile perch which can be even heavier than most giant catfish. There are indeed some strange claims about the alleged sizes of some african catfish, which are ridiculously over anything confirmed. There is for example a claim of a 270 kg Bathybagrus grandis from Lake Tanganyika. Fishbase gives a length of 63 cm...
      For Chrysichthys cranchii there are also claims of 4 m length or weights more than 180 kg. But even if this species seems to reach comparably big sizes for a freshwater fish, but 1,5 m seems much more realistic for large specimens. Those claims seems to have similarly much credibility like those for 4,5 m long wels. I do not rule out that there are indeed some species of african catfish which reach bigger sizes than we know, as there are still many areas with a poorly studied ichthyofauna, and few zoologist payed that much attention to animals like giant catfish as to lions or elephants, but we can´t hardly expect to find real monsters.

    9. I did mean of course "On the Track of Unknown Animals", and not "In Search of Hidden Animals".


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