KATHMANDU — The discovery in a Nepali river of an armored catfish native to the Amazon has alarmed researchers and conservationists, who say it’s still not clear how the species found its way from the South American rainforest to the Himalayan nation. Forty-three specimens of Pterygoplichthys disjunctivus, known as the vermiculated sailfin catfish, were discovered in the Lohandra River during surveys of various rivers in eastern Nepal from May 2019 to July 2023. The findings were documented in a newly published study in the journal BioInvasions Records. “Our study for the first time shows the presence of genus Pterygoplichthys fish in Nepal’s river system,” study co-author Asmit Subba, a zoologist at Tribhuvan University in Kathmandu, told Mongabay. “However, we can’t conclusively say where the fish came from.” Fish in the genus Pterygoplichthys are commonly called “janitor fish,” as they’re used in aquariums to eat algae and keep the tanks clean. From the Amazon Basin via the aquarium fish trade, they’ve since found their way into river systems around the world, including in South Asia, East Asia and the U.S. P. disjunctivus is adapted to living in the murky waters of the Amazon, where it swallows air and absorbs the oxygen through its intestinal linings rather than extracting oxygen from water the way most other fishes do. This ability allows it to survive even when it’s out of water for hours. “Because of its vermiculated scales, it’s very difficult to kill and not even palatable to humans,” Subba said. Forty-three specimens…This article was originally published on Mongabay
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