Protocobitis is a small genus of true loaches in family Cobitidae, known only from cave systems in the karst country of southern China's Guangxi region. Rather than the substrate-sifting stream loaches most aquarists picture, these are troglobitic fish - cave specialists that have lost much of their eye pigmentation and visual function over time, navigating instead by sensory barbels and the lateral line in total darkness. The atlas's three species - P. anteroventris, P. polylepis, and the aptly named P. typhlops, "blind eyes" - span roughly 1–3 in, sharing the elongated, slender loach body plan suited to squeezing through narrow subterranean passages.
Protocobitis has essentially no presence in the aquarium hobby; its value is scientific rather than ornamental, as a living case study in how vertebrates adapt to permanent darkness. Its conservation picture is among the more precarious in the atlas: karst caves are naturally tiny, isolated habitats, and even modest disturbance - quarrying, groundwater pollution, cave tourism - can threaten a species across its entire known range. The atlas records one Critically Endangered species, one Vulnerable, and one not yet evaluated, a pattern typical of narrow-range cave endemics with little buffer against local habitat loss.