June 23, 2025, 12:19 pm | Read time: 12 minutes
Every year, preferably in the summer, it reliably emerges from the depths of lakes, ponds, and pools: the supposedly dog-eating giant catfish. Recently, sightings of enormous specimens in Lake Garda made headlines. In nearly every city here, there’s a story about a small dog that was suddenly pulled into the depths while exploring the shore.
In Bavaria, the police intervened just a few days ago: They promptly shot a catfish that was said to have bitten swimmers. But are catfish really aggressive and do they even eat small dogs? Can they also pose a danger to humans? How do they live and what do they eat? PETBOOK consulted experts to debunk myths.
“Creature Holds Lake Garda Hostage”
If that doesn’t sound creepy: “Giant fish threaten popular tourist region,” “Monster fish in Lake Garda,” and “Creature holds Lake Garda hostage”–with such dramatic headlines, newspapers at home and abroad have been reporting for several weeks about the presence of large catfish in the popular holiday hotspot Lake Garda. Since 2019, when a British angler pulled a 115-kilogram, over three-meter-long specimen from the lake in northern Italy, reports of sightings have “virtually exploded,” as the online portal “Südtirol News” reported at the end of May 2025.1
A local fisherman recently recounted seeing an approximately two-and-a-half-meter-long, 100-kilogram animal in the lake’s waves. Since then, fishermen have feared for their livelihoods, tourists for their well-being, and the region for a decline in visitors. As a result, freedivers have now taken to hunting catfish in Lake Garda with harpoons. Neither tourists nor fishermen should feel threatened by the supposed “monster fish.”2
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A Creepy Thought
The story of the small dog swallowed while innocently splashing around, supposedly eaten by a catfish, persists stubbornly and is likely to come to mind for many Lake Garda visitors in light of the headlines. Whether in Cologne, Berlin, or Munich, almost every city has the tale of that one dachshund, either snatched while swimming or even just sniffing at the shore, pulled into the depths by a catfish. And swimmers repeatedly report being bitten and injured by a suddenly appearing giant catfish.
Admittedly, the idea that a three-meter-long, over 100-kilogram fish could suddenly appear next to you while swimming is probably unsettling to most. The creature doesn’t even need to bite. But do catfish really have an appetite for dogs and aren’t afraid to attack and bite humans?
More Than Two Meters Long and 100 Kilos
In fact, the European catfish, as the animal is precisely called (regionally also known as Wels), is particularly impressive due to its large body and wide mouth. The animals, whose zoological name is Silurus glanis, are the largest freshwater fish in Europe. Depending on the space in their habitat, they can easily reach more than two meters in length and weigh over 100 kilograms. However, most fish are at most one and a half meters long and weigh around 50 kilos. Despite their size, the animals are generally considered shy and are rarely found at the water’s surface.3
“Catfish live in the lower water layers, at the bottom, not at the top,” explains Dr. Michael Möhlenkamp, a biologist and managing director of the Westphalia and Lippe State Fisheries Association. Catfish have an elongated, usually black or gray, scaleless body covered with a layer of slime. The belly is lighter than the back. The large, flat head with a very wide mouth is striking. Around the mouth, on the upper and lower jaw, catfish have three pairs of antenna-like sensory hairs, called barbels. With these, they detect prey in murky water.
Catfish Can Live Up to 80 Years
The eyes are small, and catfish have poor vision. However, they possess a very good sense of smell and touch, so they don’t need to see well. Under optimal conditions, they can live up to 80 years, as they have no natural predators once they reach a certain size. Catfish mainly live in rivers and lakes and prefer water temperatures of at least 18 degrees Celsius. Their spawning season begins in spring and ends in July. The animals are mostly active at dusk and at night, resting during the day in the muddy to sandy bottoms of their waters.
Adult catfish are solitary and considered territorial: They actively defend their territory. Catfish lay their eggs in shallower shore areas, where they are guarded by the male. If the animals or their clutch feel threatened, they chase away intruders and will not hesitate to attack if necessary. Disturbers can expect to be bumped or, in rare cases, bitten. However, they would not be seriously injured or swallowed, assure two fish experts when asked by PETBOOK. Above all, dogs and humans need not fear being endangered by a catfish attack.
Catfish Prefer to Eat Fish
Catfish eat by opening their mouths and practically “sucking in” the passing prey, as Dr. Michael Möhlenkamp, a biologist and managing director of the Westphalia and Lippe State Fisheries Association, explains. “This happens due to the suction created when the mouth opens.” The animals are fast predators and not very picky about their prey. “They are opportunistic feeders; they take what swims in front of their mouths,” says Möhlenkamp. But these are usually fish.
In 2018, a video published by the news magazine “Spiegel Online” caused a stir, showing catfish from a southern French river hunting pigeons. The birds were bathing in the shallow shore water when catfish approached and – to snap at the pigeons – even came ashore for a short time, risking stranding themselves. However, this behavior has so far only been observed in the Tarn River and is described by experts as “highly unusual.”
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Do Catfish Also Eat Small Dogs?
Fish expert Möhlenkamp agrees. “To my knowledge, such behavior has never been observed in this country, and I am not aware of it from other regions either.” Birds are not part of the usual diet of catfish. Occasionally, a small water rat or a waterfowl chick might be swallowed.4 This is confirmed by a spokesperson for the Berlin Anglers’ Association when asked by PETBOOK. He actually once discovered the bones of a small duck in a catfish’s stomach: “That can happen, but it’s more of an accident.”
Catfish have poor eyesight, and if a group of small ducks is paddling around the lake, the catfish might mistake them for roaches or other small fish. “Then it surfaces with its mouth open among the supposed fish and might accidentally swallow a small duck,” said the spokesperson for the state association. However, the preferred prey of a catfish is not ducks or other birds. And dogs, both experts confirm, absolutely do not fit into the catfish’s diet.
“Even smaller dogs are too big for native catfish,” says a spokesperson from Berlin. The experts agree that the stories of swallowed dachshunds belong “in the realm of myths.” And humans simply do not fit into the catfish’s diet.
Catfish Protect Their Eggs
So where do the reports come from that people have allegedly been attacked by catfish? In 2016, a swimmer from Bavaria reported being attacked by a catfish while swimming.5 The woman suffered a few scrapes and a fright. Just a few days ago, there were several injuries in Weißenburg, Bavaria: At the local Brombachsee, a techno festival attracted countless guests not only to the shore but also into the water to cool off. For some, however, the refreshment ended unpleasantly: Within two hours, according to the water rescue service, five people reported being bitten by a large catfish.6
The “aggressive fish,” about two meters long according to the police, repeatedly attacked bathers near an island and became a danger to the guests. Therefore, it was decided after a few hours to kill the animal. An officer then drew his service weapon and shot the 90-kilogram Wels. Criticism of the action was not long in coming. For the operation was a sad and incomprehensible end for the animal, which apparently only wanted one thing: to protect its offspring.7
The Truth Behind the “Biting Attacks” on Humans
Because the idea that the catfish had an appetite for swimmers is dismissed not only by both fish experts consulted by PETBOOK. Apart from the fact that humans fit even less into the catfish’s prey pattern than dogs, the catfish cannot really bite with the blunt, small teeth in its mouth and certainly cannot tear pieces out of a person. It remains with abrasions and scratches. If catfish really do bite people, “it is related to the territorial behavior of the animals when they believe their eggs are threatened,” says Dr. Michael Möhlenkamp.
Because, as already described, catfish can indeed attack if they believe their offspring are threatened. If an unsuspecting swimmer gets too close to the catfish’s nest, the defensive animal may eventually snap at them if it becomes too agitated. With the number of bathers at Lake Brombach and the thumping beats on the shore, the catfish was apparently so stressed that it bit anything that came too close to it and its spawning area. However, the animal paid for its innate protective instinct toward its offspring with its life.
More Likely to Win the Lottery than Be Attacked by a Catfish
The bathers who startled the catfish, however, got off lightly. Even after the incident with a swimmer in 2016, fish experts reassured the media: Even the angriest catfish will limit itself to a brief attack and will not engage in a fight with a competitor as large as a human. And even a simple defense, reassures the spokesperson for the Berlin Anglers’ Association, “is extremely rare, because catfish do not lay their eggs on busy beaches where people gather daily.” The animals are too shy for that.
However, those who go into the water in remote areas or use lakes that are not open for swimming may encounter a catfish or other animals defending their habitat. Just like at Brombachsee. The countless guests of the techno festival who used the lake to cool off had simply disturbed the catfish living there during the spawning season, as Robert Arlinghaus from the Leibnitz Institute for Freshwater Ecology and Inland Fisheries also explained in an interview with BILD.
As early as 2024, he described the likelihood of being attacked by a catfish in a contribution for the TV station MDR with a striking comparison: “You are more likely to win the lottery than for that to happen.” But if it does happen that a catfish bites, the story naturally spreads, says the spokesperson for the Berlin Anglers’ Association.
The Thing About Legends
Therefore, he attributes the legend of the dog-eating catfish primarily to exaggerations and a lack of knowledge. “If a small dog perhaps didn’t make it back to shore while swimming and drowned, it is still said that it was the catfish. If a swimmer gets injured while swimming, it was the catfish.” Whether that’s true is rarely checked, but the story is always embellished further, “until finally a huge monster devours an entire lake.”
And even some anglers themselves contribute to the legend: “When they pull a catfish ashore, it’s barely a meter long. On the way home, it’s already two, and in the evening at the angler’s lodge, their arms aren’t long enough to show the length of the animal.”
Fishermen See Catfish as a Threat to Their Livelihoods
For fish experts, it is clear despite numerous reports and rumors: “Neither dogs nor humans are in danger from catfish.” Not while swimming, not while paddling, and certainly not while walking along the shore. “Catfish do not come ashore,” says the Berlin Anglers’ Association. Their spokesperson has never experienced a catfish snatching a dog. Nor has he ever found dog bones in a catfish’s stomach or heard of such a find.
However, catfish do indeed have a big appetite. They devour what lives in their pond, and in large quantities. That is the real problem with catfish and especially for fishermen, who–like at Lake Garda–see their livelihoods threatened as a result. Environmental experts also fear that larger catfish populations could harm biodiversity in affected waters. Smaller fish species such as roach and rudd, as well as young predatory fish like pikeperch and pike, could be endangered by the catfish.8
Catfish Are Tough Fish
Catfish could also have a negative impact on the population of some endangered amphibians. Incidentally, catfish, originally from the Danube region and Eastern Europe, were not native to most of the waters where they are now found. However, because they are considered popular and tasty food fish, they have been increasingly introduced by anglers into numerous lakes and ponds since the 1970s.
There, they found very good living conditions, not least due to increasingly warmer summers and mild winters, and multiplied rapidly. The animals are also considered quite resistant to water pollution and can cope with lower oxygen concentrations than other fish. Catfish particularly appreciate waters with low currents that warm up more quickly, as their comfort temperature is between 25 and 27 degrees Celsius.
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Catfish as Winners of Global Warming
Thus, the catfish could become a winner of global warming. Studies indicate that the animals grow faster and larger in warmer waters and reach sexual maturity earlier. As a result, they reproduce better than other, less adaptable fish species. Additionally, their habitat is shifting to higher, once cooler, and now also warmer regions where they were not previously widespread.
Unlike other native predatory fish, the catfish is not particularly picky about its food, so it finds food almost everywhere. Conveniently for it, numerous weirs, locks, and fish ladders can be found in local waters, as Robert Arlinghaus from the Leibnitz Institute for Freshwater Ecology and Inland Fisheries explained to the TV station MDR.
The catfish only needs to wait there until salmon, trout, and other migratory fish species pass by. In some places, there are “high feeding losses.” Currently, trout, eels, and salmon are being reintroduced with great effort to compensate for past environmental destruction. Here, the catfish can cause significant losses, thwarting conservation efforts.