For over half a century, people in Central Africa have told tales of the fish seen climbing waterfalls, but these claims have never been officially confirmed. Now, these fish have finally been caught on camera, studied more closely, and described in a study published in Scientific Reports.

An arduous vertical journey
The shellear fish (Parakneria thysi), found in the upper Congo Basin, are tiny 37–48 mm-long fish that can grow up to a size of around 96 mm. Researcher Pacifique Kiwele Mutambala from the University of Lubumbashi in the Democratic Republic of the Congo and his team documented the shellear fish climbing waterfalls from 2018–2020. In particular, the fish were recorded scaling the Luvilombo Falls on the Luvilombo River, which is a 50-foot (15 meter) waterfall. Thousands of shellear were seen migrating upstream, clinging to wet rock surfaces in the splash zone.