Biotopes Underwater

From the Plains to the Himalayas Eleven years ago, a pair of swimming goggles and a pond near his home changed everything. Sourav Ghosh has spent every year since diving into India's freshwater world — and what he's found beneath the surface rarely looks like what's expected.

By Sourav Ghosh

Estimated read time: 3–4 minutes

The journey into India's underwater world began eleven years ago with nothing more than a pair of swimming goggles and flippers. Curious about what lay beneath the surface, Ghosh dived into a pond close to his home. The clear water revealed an entirely different world — one filled with native fishes, aquatic plants, and hidden interactions that most people never get to witness. That first dive didn't just make him an Indian native fish enthusiast. It sparked a passion for underwater photography that would eventually take him from small urban ponds in Bengal to the cold, crystal-clear rivers of the Himalayas.

A Pond, Reconsidered

The pond that started it all sat surrounded by residential apartments, reinforced with bamboo, its banks lined with thick grasses — about as ordinary as urban water gets. But spend enough hours watching it, camera in hand, and an unexpectedly rich habitat began to reveal itself: native fishes sharing space with dense native aquatic flora, thriving despite — or perhaps because of — its overlooked, human-modified setting. It was the first proof of something that would define the next decade: even the most unremarkable water body can hide a world worth documenting.

A Wetland That Breathes With the Seasons

About eight kilometres from home lies Shyamkhola — a former brick excavation site that nature slowly reclaimed into a 13.5-hectare wetland. Over several years of visits, Ghosh watched the habitat transform dramatically with the seasons: monsoon floods opening up breeding grounds, winter drawing in migratory birds, summer shrinking the wetland down to scattered, muddy refuges. The same stretch of water, three entirely different underwater worlds — depending only on when you looked.

Into the Plateau, and Beyond Bengal

As his exploration widened beyond Bengal, the plateau streams of Chhattisgarh offered something completely different — clear water flowing gently over lateritic rock, dense sal and teak forest overhead, and a first underwater glimpse that turned up schools of Zebra Danios and the discovery of Schistura denisonii, Denison's Loach.

The Himalayas Change Everything

Nothing prepared him for the fast-flowing rivers of the north. His first major Himalayan exploration took him to the Reshi Khola, a river forming part of the border between Sikkim and West Bengal — and it took an entire extra day just to gather the courage to enter the cold, turbulent water.

“So captivated were we by the scenery that we barely noticed the leeches attached to our feet.”

Higher still, at a mountain village called Rongo — 1,370 metres above sea level — Ghosh found water so clear it measured just 11 parts per million in dissolved solids. At first, there seemed to be no fish at all. Then the shadows beneath the boulders began to move.

A World Most People Never See

Eleven years, and one thread runs through all of it: every river tells its own story. Even habitats that look superficially similar can harbour completely unique communities, shaped by geology, elevation, flow, and water chemistry most of us will never think to notice.

Watch & read the full story

Watch the SNL interview with Sourav here — From Bengal Wetlands to Himalayan Streams Read the full story in the June 2026 issue of The Weekend Aquarist.

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