A recent study on the bumblebee catfish (Rhyacoglanis paranensis) has revealed a remarkable behavior where these small, striped fish climb up the sides of waterfalls in great numbers. Measuring less than 9 centimeters long, this species is usually found in fast-flowing rivers, making it challenging to study.
The research team observed thousands of bumblebee catfish climbing rocks and vertical surfaces during the rainy season in November 2024. Notably, they saw a significant increase in activity from 6 pm onwards, suggesting that these fish adapt their behavior according to environmental conditions.
Researchers discovered that the bumblebee catfish spread their fins wide open to climb the rocks, creating a negative pressure space between their body and the rock surface. This phenomenon helps them remain attached.
The study suggests that the mass migration upstream is related to spawning, as observed in the empty stomach contents of the fish during this period. The team also identified three other species displaying similar climbing behavior for the first time.
This remarkable ability joins “walking” and “flying” as unexpected skills demonstrated by fish, highlighting the complexity and adaptability of these aquatic creatures.
Source: https://www.iflscience.com/thousands-of-bumblebee-catfish-seen-literally-climbing-the-walls-for-the-first-time-ever-80468