Pangio is a genus of small, worm-shaped loaches from Southeast Asia and South Asia, commonly known as kuhli loaches. The atlas covers 36 species, ranging from about 1 in up to 5 in, drawn from countries including Malaysia, Indonesia, India, Thailand, Myanmar, Brunei, Singapore, and Bangladesh — reflecting a range that stretches from the Indian subcontinent across the Malay Peninsula and into the Indonesian archipelago. What unites the genus is an elongated, eel-like body with a greatly reduced or absent scale covering, tiny eyes, and a slender profile built for pushing through leaf litter, sand, and root tangles on the floor of slow, shaded forest streams. Most species are nocturnal or crepuscular, spending daylight hours buried or hidden and becoming active as light fades.
The genus is a mainstay of the freshwater aquarium hobby: Pangio kuhlii, the kuhli loach, is one of the most widely kept bottom-dwelling fish in the trade, valued for its peaceful nature, its habit of sifting through fine substrate, and its willingness to work alongside almost any other peaceful community fish. Close relatives such as Pangio semicincta (the half-banded kuhli loach) and Pangio oblonga (the Java loach) are also regularly available and share the same easy-going, substrate-sifting character, generally doing best in soft, slightly acidic water over a fine sand bed with plenty of hiding places. Conservation status is mixed but not alarming overall: the atlas records mostly Least Concern and Data Deficient species, with a smaller number classed as Vulnerable, Near Threatened, or Endangered.