In north-east India, a doctoral student carries water from a well she dug herself. When she pulls up the bucket, a tiny, pale fish swims in it. Only 20 millimetres long, transparent, with severely reduced eyes. And, as it later turns out, without a bony skull roof. A creature that science had never seen before.
Dr. Ralf Britz from the Senckenberg Natural History Collections in Dresden was on a research trip to the region in 2024 when he was shown the fish. “I was immediately sure that this was a very special find,” he says. Together with his Dresden colleague Dr. Amanda Pinion and Indian researcher Velentina Kangjam, he has now scientifically described the fish. The new species is called Gitchak nakana and belongs to the loaches, a group of small freshwater fish.
A milestone for research
“The tiny, blind loach is so unique that it represents not only a new species but even a new genus,” adds Britz. India ranks fourth worldwide in the diversity of subterranean fish species. Until now, such animals were mainly known from the north-east and south-west of the country. Gitchak nakana is now the first known groundwater fish from the Assam region.
The discovery suggests that there may be many more unknown species living in the aquifers of this region. “The discovery suggests that this region may host a highly specialized subterranean fauna that now needs to be explored.”
Original publication:
Publication: Britz, R., Marak, W.K., Velentina, K. et al. A miniature, subterranean, blind cobitid loach, Gitchak nakana, new genus and species, is the first groundwater-dwelling fish from Northeast India. Sci Rep 16, 7746 (2026).
