Close-up view of catfish "giving birth" and climbing a 4-meter-high waterfall ( Video : Science Alert).
A rare discovery in the natural world has just been recorded in Brazil, when thousands of bee catfish ( Scientific name: Rhyacoglanis paranensis ) simultaneously overcame a waterfall up to 4 meters high on the Aquidauana River.
Images of these catfish, measuring less than 4 cm in length, persistently climbing sheer cliffs have led scientists to compare them to "Olympic mountaineers."
This unusual event was initially discovered by local police in the dead of night. Subsequently, researchers from Mato Grosso do Sul Federal University immediately arrived to monitor the phenomenon for 20 consecutive hours.
Direct observation revealed that the black and orange striped fish gathered in dense concentrations, with many even piling on top of each other in large clusters to climb over the waterfall's rocky steps.
Biologist Manoela Marinho described in detail how these fish climb the waterfall in such a peculiar way. Initially, the small fish spread their fins wide like an anchor to firmly grip the slippery surface, while vigorously wriggling their bodies to propel themselves upwards.
Scientists suspect that the fins of this fish species have a suction mechanism that helps them cling to the water. Thanks to this, they can persistently move forward little by little up the steep waterfall. Remarkably, they even managed to climb onto a bucket of water placed near the waterfall, demonstrating their incredibly strong instinct to swim against the current.
The unique biological mechanism enables the bee catfish to overcome steep waterfalls (Photo: Getty).
Analysis of fish samples revealed that the majority of individuals participating in the waterfall climb were adult fish with empty stomachs. This suggests reproductive migration behavior, similar to the well-known migration of salmon, which forgo eating during their arduous upstream journey.
Research suggests that fasting allows the fish's body to concentrate maximum energy on navigating rapids and maintaining endurance in harsh environments. Furthermore, it helps to minimize the fish's body weight.
Marinho and colleagues emphasize that small, migratory fish species like the bee catfish often go unnoticed because their behavior occurs over short periods and in specific environmental conditions that are difficult to observe.
However, these rare records are of great value in better understanding the ecological role and conservation needs of biodiversity in tropical river ecosystems.
According to scientists, this discovery also raises concerns about the threats faced by small fish species. Specifically, habitat fragmentation due to hydroelectric dam construction and changes in river flow are significant factors that can hinder migration and lead to population decline.
If this fish species disappears, the freshwater ecosystem will lose a crucial link in the food chain and the natural balance.
Source: https://dantri.com.vn/khoa-hoc/dan-ca-tre-vuot-can-leo-thac-nuoc-cao-4-met-20250826100249660.htm
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