Catfish "give birth" and climb a 4 meter high waterfall

(Dan Tri) - The catfish are less than 4 cm long but still persevere in climbing up the steep cliff.

Close-up of a school 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 passed over a 4 meter high waterfall on the Aquidauana River.

Images of catfish less than 4cm long but still persistently climbing up steep cliffs have led scientists to compare them to “Olympic climbers”.

The unusual event was initially discovered by local police in the dark of night. Researchers from the Federal University of Mato Grosso do Sul were then immediately present to monitor the phenomenon for 20 consecutive hours.

Direct observation shows that schools of black and orange striped fish gather in dense groups, with many even piled up on top of each other in large clumps to climb over the waterfall's stone steps.

Biologist Manoela Marinho has detailed this strange climbing method. Initially, the small fish spread their fins wide like an anchor to grip the slippery surface, while vigorously wriggling their bodies to push themselves up.

Scientists suspect that the fins of this fish have a suction mechanism that helps them to persevere and advance bit by bit up the vertical waterfall. Remarkably, they can even climb onto a bucket of water placed near the waterfall, showing that their instinct to swim upstream is extremely strong.

Special biological mechanisms help catfish have the ability to overcome steep waterfalls (Photo: Getty).

Analysis of fish samples showed that most of the fish involved were adults with empty stomachs, suggesting that this was a spawning migration, similar to the famous salmon migration, which forgoes feeding during the arduous journey upstream.

Research shows that fasting helps the fish's body concentrate maximum energy on crossing the rapids, and maintain endurance in harsh environments. Not only that, this also helps reduce the fish's body weight to the maximum level.

Marinho and colleagues emphasize that small migratory fishes such as the bee catfish are often overlooked, because their behavior occurs over short periods of time and under specific environmental conditions that are difficult to observe.

However, these rare records are of great value in better understanding the ecological role and need for biodiversity conservation in tropical river ecosystems.

According to scientists, this discovery also raises concerns about the threats facing the small fish. Typical examples include habitat fragmentation due to hydroelectric dam construction, as well as changes in river flows. These are factors that can hinder migration routes, reducing populations.

If this fish disappears, freshwater ecosystems will lose an important link in the food chain and natural balance.

Source: https://dantri.com.vn/khoa-hoc/dan-ca-tre-vuot-can-leo-thac-nuoc-cao-4-met-20250826100249660.htm