Triplophysa is a large genus of stone loaches in the family Nemacheilidae, centered on the rivers, cold mountain streams and karst cave systems of the Tibetan Plateau and surrounding highlands. The atlas covers 157 species spread across China, India, Pakistan, Afghanistan, Kyrgyzstan, Uzbekistan, Kazakhstan and Iran, making it one of the most widely distributed loach genera in Central and High Asia. Body form varies with habitat: typical species are small, elongate bottom-dwellers built for cold, fast water, while a notable subset, including several cave-adapted species, have reduced or absent eyes and pale, depigmented bodies, an adaptation seen repeatedly across the genus wherever populations have colonized groundwater and caves. Size in the atlas ranges from about 1.5 in up to 19.5 in, a wide spread reflecting how ecologically varied the genus has become.
Most Triplophysa are of far more interest to ichthyologists and cave biologists than to the aquarium trade; only a small handful, like the Chinese cave loach (T. dongganensis) and the blind cave loach (T. erythraea), turn up in specialist circles interested in cave-dwelling fish. These cave and groundwater species are typically narrow-range endemics, often confined to a single cave system or spring, which makes them inherently vulnerable even where formal assessment hasn't caught up: the atlas tally is dominated by Not Evaluated species (100 of the total), with smaller numbers already confirmed Endangered or Critically Endangered. As with many high-altitude Asian genera, Triplophysa's known species count has grown steadily as more remote drainages and caves get surveyed.