Rare albino stinging catfish recorded in Assam’s Brahmaputra valley
Guwahati: Researchers have documented two rare cases of total albinism in the stinging catfish Heteropneustes fossilis (locally called Singee) from the Lesia river in Dhemaji district, marking only the third confirmed occurrence of total albinism in this species in India.
The specimens, about 13 cm long, were landed by local fishermen during routine netting in January 2024.
Unlike typical dark-coloured Singee, both fish were entirely pale white with reddish eyes and fins, classic signs of total albinism in fishes, where the absence of pigmentation makes underlying blood vessels visible in the eyes.
Albinism in freshwater fish is globally uncommon and may stem from genetic mutations or environmental stressors, such as heavy-metal contamination.
Most recorded cases worldwide occur in catfish (order Siluriformes); in India, documented instances of total albinism are rare and include cave fishes from Meghalaya and occasional surface-dwelling species, such as Clarias batrachus (Magur) and Anguilla bengalensis (freshwater eel).
For H. fossilis, the Dhemaji discovery follows only two earlier reports: one from Assam in 1966 and another from West Bengal in 2023, underlining the exceptional nature of the find, the authors say. The observations are described in a paper published in the Journal of Wildlife Science.
The stinging catfish is an important food and ethnomedicinal resource in Assam. Local communities, including the Mising, Sonowal-Kachari, and Deori, prize the species for its nutritional value.
Market prices typically range between Rs 500 and Rs 1,000 per kg. The study notes traditional beliefs that the fish can benefit pregnant and lactating women and help treat anaemia and general weakness.
Despite its cultural and economic value and an IUCN listing of “Least Concern,” populations of H. fossilis face mounting pressures from habitat degradation, overfishing, and river infrastructure projects.
Assam contains roughly 100,000 hectares of floodplain wetlands, including oxbow lakes, marshes, and fens, and Dhemaji alone has more than 79 wetlands covering about 119 hectares, important refuges where local fishers commonly hunt for Singee.
The study warns that seasonal movements heighten vulnerability. With the onset of the monsoon in April, mature individuals migrate to find spawning grounds and are more likely to be caught.
During the rains, passive fishing gears, such as gill nets, are widely used. In winter months, dewatering and shrinkage of aquatic habitats further stress wild stocks.
The authors call for monitoring of wetland habitats, community awareness, and tighter management of fishing practices to protect both common and anomalous individuals.
Researchers say the albino specimens offer a rare window into genetic and environmental dynamics in freshwater systems and underscore the need to conserve the wetland habitats that sustain Assam’s culturally important fisheries.