- A TikTok video led to the discovery of a new fish species resembling an earthworm
- The species, Gangaichthys indonepalicus, was found near the India-Nepal border in 2024
- The fish evolved in total darkness with reduced eyes and moves by wriggling through sediment
A video uploaded to TikTok led researchers to discover a new species of fish that looks and behaves like an earthworm. The animal, named Gangaichthys indonepalicus, was first spotted in 2024 online, IFLScience reported. The video, filmed near the border region of India and Nepal, showed a tiny, pale creature that had washed out of a borewell, a deep hole drilled into the ground to draw drinking water from underground aquifers. The scientists suspected it was a completely unknown species because it emerged from pitch-black groundwater and lacked typical fish traits.
But according to the details published in the journal ZooKeys, this unusual fish evolved different characteristics as it lived in total darkness deep under the Earth's surface.
An international team of scientists from the Thackeray Wildlife Foundation in Mumbai, India; Shivaji University in Kolhapur; the Shanghai Synchrotron Radiation Facility at the Chinese Academy of Sciences; and the Zoological Survey of India in Gopalpur-on-Sea came together to carry out the research.
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"The unique morphology of the fish in the video, and the fact that there are no known stygobitic fish known from the region, motivated us to track down the species to ascertain its identity," the research team said as quoted by EurekAlert.
"Procuring samples of this unusual fish was challenging," said researcher Akshay Khandekar of the Thackeray Wildlife Foundation.
"Identifying potential handpumps (borewells) and wells, and obtaining permission from their owners to extract water for the purpose of searching for the fish proved difficult. This became more intensive when we finally began manually pumping water."
"The first specimen emerged after pumping approximately 2000 litres of water but sustained damage during the process and died immediately. The second and only intact specimen (later designated as the holotype of this species) was found from the same borewell after pumping an additional 500 litres of water."
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As per the research, the newly described fish measures roughly four centimetres. The species has almost no need for sight, resulting in tiny, heavily reduced eyes.
Lacking large fins, the animal moves by wriggling through saturated soil and water-filled sediment layers.
Although it looks like an earthworm, micro-CT scanning and genetic analysis confirmed that it represents a completely distinct genus within the earthworm eel family Chaudhuriidae.
"Gangaichthys means fish of the Ganga," Agarwal explained the naming.
"The Ganga or Ganges is one of the most important rivers in India, both as a source of fresh water, food and livelihood for millions of people; besides having an important role in the Hindu religion. This is the first stygobitic fish from the Indo-Gangetic plains and from the Gangetic basin."
