Stunning Footage: Watch Thousands of Bumblebee Catfish Scale a Waterfall for the First Time!

Recently, astonishing footage emerged of thousands of bumblebee catfish climbing a waterfall in southern Brazil. This is the first in-depth look at their migration behavior.

Bumblebee catfish, or Rhyacoglanis paranesis, are small fish with striking black spots on their orange bodies. They grow to about 3.5 inches (89.2 mm) long. In the video, these tiny fish were seen leaping up slick rocks, reaching heights of 3.3 to 13.1 feet (1 to 4 meters) by a waterfall on the Aquidauana River.

Little is known about this rare species. In 2024, Brazilian Environmental Military Police spotted the fish climbing and called in scientists to study the phenomenon. Their findings were published on August 8 in the Journal of Fish Biology.

The Rhyacoglanis genus includes nine small catfish species found in South America’s major river basins. According to biologist Manoela Marinho, this behavior was surprising because previous observations were scarce. “The large gathering we observed is remarkable, as it had never been documented before,” she shared.

The research revealed that the catfish typically climbed in the evenings. During the hot afternoons, they sought shade under rocks. As the sun dipped, thousands began their ascent.

The fish started from small pools, jumping up steep rock faces and even piling on top of each other. Their climbing frenzy even included some catfish clambering onto the scientists’ equipment.

To navigate the rocks, these catfish used their fins and a rocking motion. Scientists think they might create suction against the rocks, a technique shared by some other river fish like stream loaches and Andean climbing catfishes.

Although the exact reason for their climb is unknown, researchers believe the fish were migrating upstream to spawn. Most of the climbers were adults, and this behavior began in November, coinciding with the rainy season after a long drought.