I have always loved animals. A habit that goes back to my school-going days. I would buy books about wildlife. Spend hours reading articles about remote sanctuaries. Cut out pictures of tigers and wolves. Or try drawing them. But the hobby of fish-keeping introduced me to a hitherto concealed part of the natural world. It was not that I did not know anything about fishes. I had heard of the Great White Sharks and Red Bellied Piranhas. Seen documentaries about migrating Sockeye Salmon and gigantic Bluefin Tuna. But my knowledge about river-dwelling fishes was rather meagre.

Apart from the fish that ended up on our plates at home (being Telugus from South India, my family had a healthy appetite for the likes of Rohu – Labeo rohita, Catla – Catla catla, and Sareng – Wallago attu), I knew only a handful. All of this changed when my brother made me clean up an old aquarium lying near our apartment. This was followed by attempts to raise Goldfish (Carassius auratus). Unfortunately, the first batch my brother purchased died. But our trips to the aquarium opened up our eyes. There was more to keep in a tank than just colourful carps.

Among the more unusual species of fish that we tried raising were the Kuhli Loaches (Pangio kuhlii). They are members of the genus Pangio, of the family Cobitidae. The Cobitidae or true loaches are close relatives of the carps (family Cyprinidae). Unlike carps, they are eel-like in appearance, with elongated bodies and bottom-facing mouths, living on the river bed. Like their large cousin, the Clown Loach (Chromobotia macracanthus) of the family Botiidae (soldier loaches), they have an erectile spine underneath the eyes. They are benthic omnivores, feeding on detritus, crustaceans, insects and worms on the river bed. Their unusual shape is an adaptation to their lifestyle.

I had never expected seeing a freshwater fish so eel-like as the Kuhli Loaches. Eels (of the order Anguilliformes) are mostly oceanic, with only a few members of the genus Anguilla being found inland. Like the Clown Loach, the Kuhli Loach is a native of South East Asia. It lives in the hill streams, lowland rivers and peat swamps of the Malay Peninsula, Sumatra and Java. Unlike most aquarium fish, they are secretive, preferring to hide among plants and underneath the sediment, from where they emerge to feed at night. But it’s a striking species, with its snake-like style of swimming, and chocolate brown stripes on a yellowish-pink body. The species and genus reveal the success of the order Cypriniformes which have diversified and occupied a wide range of habitats and niches in the rivers, lakes and swamps of the world.

Image Attribution: The image above is sourced from Wikimedia Commons and shows the illustration of a Kuhli Loach from Dutch ichthyologist Pieter Bleeker’s ‘Fishes of the Indian Archipelago’. Posted as a medical officer of the Royal Netherlands East Indies Army in Indonesia (1842-1860), Bleeker used to collect specimens from local fishermen. After his return to the Netherlands, he published his monumental Atlas Ichthyologique des Indes Orientales Néerlandaises, featuring over 1,500 illustrations in 36 volumes. This particular image was published by Zoologische Mededelingen.