A giant bluefin tuna weighing nearly 300 kilograms came frighteningly close to swimmers at a beach in Marbella, Spain. But experts say the fish was likely not hunting anyone – it was probably in serious distress.
A seemingly bizarre scene unfolded at El Ancón beach on Marbella’s famous Golden Mile, where a swimmer suddenly found himself being followed through the shallow water by what appeared, at first, to be a large shark.
Video of the incident shows the man swimming urgently toward the shoreline as the enormous animal moves behind him. For people watching from the beach, the scene had all the ingredients of a classic shark attack.
It wasn’t a shark. It was a giant bluefin tuna, estimated at around 295 kilograms (650 pounds) and more than two meters long. And there is an important detail that changes the story completely: the tuna appeared to be badly injured.
The Fish Wasn’t Hunting the Swimmer
According to reports from the scene, the tuna was bleeding heavily around its gills, with the water around it turning red as it struggled in the shallows.
Witnesses suggested that the animal may have been injured by fishing equipment or possibly struck by a jet ski. The precise cause of the injuries has not been established publicly.
That distinction matters. Bluefin tuna are powerful open-water predators, capable of extraordinary bursts of speed, but there is no indication that this particular fish was trying to attack the swimmer.
Instead, its unusual behavior is consistent with an animal that may have been injured, disoriented or struggling to control its movements. When a large pelagic fish is injured, particularly around the gills, normal swimming behavior can become severely compromised.
The animal may move erratically, head toward shallower water or repeatedly change direction. To a swimmer suddenly sharing the water with a 2-meter-plus fish, however, that distinction is academic. The result looks terrifying.
Why Would a Bluefin Tuna Come So Close to a Beach?
Bluefin tuna are not normally animals people associate with the shoreline. They are highly migratory fish that spend much of their lives moving through the open ocean.
But their presence relatively close to shore is not inherently impossible. The Mediterranean is part of the natural range of Atlantic bluefin tuna, Thunnus thynnus, and Spain has a major bluefin tuna fishery.
In fact, Spain’s 2026 management rules specifically regulate bluefin tuna fishing in the eastern Atlantic and Mediterranean. The country’s allocated quota for 2026 is nearly 7,939 metric tons, illustrating just how significant the species is in the region.
So the extraordinary part of the Marbella encounter wasn’t necessarily that a tuna was in the area. It was the condition of the animal and how close its distress brought it to people.
Fishing Gear May Explain What Happened
One of the leading possibilities raised by witnesses is that the tuna became entangled with fishing gear or was otherwise injured by human activity. That remains a theory rather than a confirmed explanation.
But injuries caused by fishing equipment are a well-known problem for large marine animals. NOAA, for example, notes that fishing gear can interact with bluefin tuna and that measures are specifically used to reduce accidental capture and bycatch of the species.
A collision with a personal watercraft is another possibility mentioned by people who saw the fish. Again, there is no publicly established evidence that a jet ski caused this particular injury. The important point is that the fish was visibly in trouble.
The Most Remarkable Part Came After the Panic
Once beachgoers realized that the enormous animal was not an attacking shark but a distressed tuna, the mood reportedly changed. Instead of fleeing from it, people attempted to help.
The tuna eventually became stranded in the shallow sandy water. Beachgoers used sun loungers and deck chairs to push and guide the animal back toward deeper water.
It is an unusual ending to what initially looked like a scene from Jaws. A swimmer ran for his life. A crowd watched in panic. And then the same crowd effectively turned into an improvised rescue team.
Why the Fish Appeared to “Follow” the Swimmer
This is probably the most misleading part of the viral footage. The video makes it look as if the tuna is deliberately pursuing the swimmer. But following and chasing are not necessarily the same thing.
A severely stressed fish can move unpredictably. If it is struggling to maintain normal swimming behavior, changes in water depth, currents, obstacles and the movements of other animals can all affect its trajectory.
The swimmer was also moving in exactly the direction the fish ultimately needed to go – toward the shallows. That can create the visual impression of a predator pursuing prey, even when the man and the fish are simply moving along the same path.
There is another clue: once the tuna reached very shallow water, it reportedly began thrashing and struggling rather than attacking anyone. The fish was subsequently pushed back toward deeper water.
The Fish Itself Is Impressive
The animal appears to have been an Atlantic bluefin tuna, one of the largest and fastest tuna species. A specimen weighing around 295 kilograms is enormous, but not outside the biological capabilities of the species.
Bluefin tuna are built for sustained, high-performance swimming, with streamlined bodies and powerful musculature. That also helps explain why an injured individual can become such a dangerous-looking presence even when it has no intention of harming a person.
A 300-kilogram animal moving unpredictably through shallow water has an enormous amount of momentum. For the swimmer, it doesn’t matter whether that animal is a shark, a tuna or a dolphin. Being in its path is not a situation anyone wants to be in.
A Frightening Encounter That May Actually Be a Story About Marine Distress
The Marbella incident is a useful reminder of how quickly viral footage can distort what is actually happening in the water. The first impression is simple: Giant fish chases swimmer.
The more complete picture is considerably more complicated: A giant tuna, apparently injured and bleeding, entered shallow water, moved erratically around swimmers and eventually became stranded before beachgoers helped return it to deeper water.
The exact source of the injuries remains unclear. But if fishing gear or a collision was responsible, the episode also highlights a less entertaining reality behind the viral video: human activity can turn even a powerful ocean predator into an animal desperately trying to survive.
For a few minutes on a Marbella beach, that struggle looked like a shark attack. It wasn’t. It was something arguably more unusual – a nearly 300-kilogram bluefin tuna in distress, inadvertently terrifying an entire beach while trying to find its way back to open water.
