Beaufortia is a genus of small hillstream loaches, adapted to cling to rocks in fast, well-oxygenated mountain streams; the atlas draws records from China, Vietnam, Borneo, and more broadly Southeast Asia. Like other members of their family, they have a flattened, saucer-shaped body and enlarged, wing-like pectoral and pelvic fins that spread out to form a suction surface, letting them hold position against strong current on rock faces while grazing algae and biofilm — the trait behind the popular name butterfly loach applied to several species. They stay small even as adults and are confined to fast-flowing, cool-to-moderate, highly oxygenated water rather than the sluggish lowland habitats many other loaches tolerate. The atlas covers 18 species, adult size roughly 1–3 in.
Beaufortia kweichowensis, the butterfly hillstream loach, is the genus's one true aquarium staple, popular in planted stream-tank and high-flow biotope setups for its unusual disc-like shape, algae-grazing habit, and tolerance of cool water; B. szechuanensis and a few other species appear occasionally under the same general care approach. Keeping them well means replicating their native torrent habitat as closely as practical — strong current, high dissolved oxygen, a rocky substrate for grazing, and stable, moderate temperatures rather than typical tropical warmth. Conservation data are thin for most of the genus, with the atlas's IUCN tally mostly Not Evaluated and Data Deficient and only two species assessed as Least Concern, so there is not yet a clear range-wide threat picture.