Parakneria thysi shellear fish scale 15 m Luvilombo Falls in Congo Basin

Key facts

• Thousands of Parakneria thysi, a shellear fish species, climb the 15 m (50 ft) Luvilombo Falls in the Democratic Republic of Congo.
• Observations were recorded in April–May 2018 and 2020 during seasonal floods at the end of the rainy season.
• Only small to medium-sized fish (3.7–4.8 cm) ascend; larger individuals about 9.8 cm are too heavy to climb.
• Fish use pectoral and pelvic fins plus tiny hook-like unculi to grip wet rock in the splash zone and wiggle upward.
• A single fish may take nearly 10 hours to reach the top, resting frequently and risking fatal falls from sudden water jets.
• Lead author Pacifique Kiwele of Université de Lubumbashi published the findings in the journal Scientific Reports.
• Threats to the species include illegal fishing with fine-mesh mosquito nets and water extraction for irrigation depleting the Luvilombo River.