IWN Daily Digest — Tuesday, 20 October 2026
Two blind fishes living in village wells in Assam have been described as new to science, offering a look at a groundwater world that pollution and over-pumping could erase before anyone has catalogued it.
As reported by Mongabay India, on how Wimarithy K. Marak, a resident of Goalpara district who later became a researcher, first met one of them:
“She simply thought of it as a worm infesting her locality. In 2021, after she became a researcher, she stumbled upon the creature again while drawing water from a well.”
The creature was Gitchak nakana, a two-centimetre blind loach from a well in Goalpara, in Assam. The first specimen was collected in March 2021, according to the article. A second species, Rakthamichthys anchi, is a blind, slender, eel-like swamp eel of the family Synbranchidae, also from a Goalpara well, and its roughly 310 mm holotype was collected in May 2024 when a well was drained. Both were described in papers published earlier this year, and Mongabay India names the German ichthyologist Ralf Britz as lead author of each.
The wells sit in alluvial deposits, which Britz calls “a quickly changing environment” in which “it is difficult to imagine how a subterranean fauna evolved.” Co-author Kangjam Velentia withheld the exact location of the wells because the populations “might be exploited”.
Villagers often mistake such fish for earthworms or young snakes, and Rajeev Raghavan, a professor at the Kerala University of Fisheries and Ocean Studies in Kochi and a co-author on the G. nakana paper, says people may assume fish like R. anchi are toxic and kill them on sight. He adds that groundwater fish are likely to be the first animals to register small changes in water quality. If pollution and groundwater extraction go unregulated, he says, “we would lose a lot of species” before they are discovered.
Prerona Das, a geologist at North-Eastern Hill University, says groundwater deeper than about 200 metres is poorly mapped in Assam and the wider north-east. Grant Hose, an aquatic ecologist at the University of Sydney who was not involved in the studies, suggests sampling environmental DNA from purged wells to find out whether the fish live in the aquifer itself.
Sources: Mongabay India
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