Taxonomy & naming
The species was described by Zhu and Wang in 1985, in Acta Zootaxonomica Sinica, as Noemacheilus shuangjiangensis, from material collected in the Xiaohei-jiang river mainchannel in Gengma County, Lincang Prefecture, Yunnan Province, China. Noemacheilus was for decades a wastebasket genus for Asian stone loaches, and as taxonomists have picked that genus apart species by species, this one has moved house more than once — it has at various times been placed in Schistura and in Physoschistura before current usage settled on Nemacheilus.
It sits in Nemacheilidae, the stone or brook loach family, by a wide margin the largest family in the loach superfamily Cobitoidea and one still being actively revised. Readers encountering the older name Noemacheilus shuangjiangensis in older literature or aggregator records should treat it as this same fish under a since-abandoned combination; this article follows the current placement in Nemacheilus.
This fish was long listed as Nemacheilus shuangjiangensis; Eschmeyer's Catalog of Fishes places the species in Zhustura, and the current combination Zhustura shuangjiangensis is followed here.
Morphology
Detailed morphological data for this species have not been compiled here beyond its placement in Nemacheilidae, and no verified maximum length or distinguishing pattern description is available from the sources consulted. Like other members of its family it can be expected to share the basic stone-loach body plan: an elongate, subcylindrical body, a small ventral or subterminal mouth ringed with barbels for probing the substrate, and — in many but not all nemacheilids — a small erectile spine near the eye. Rather than guess at specifics that are not documented, this profile flags the gap honestly: this is a genuinely data-sparse species, known mainly from its original description and subsequent taxonomic bookkeeping rather than from focused biological study.
Habitat
The type locality is the Xiaohei-jiang, a river channel in the upper Mekong (Lancang) drainage in Gengma County, Yunnan, in southwestern China — a mountainous region where Nemacheilidae species typically occupy fast-flowing, cool, clear, well-oxygenated streams over sand, gravel or rock. Species in this genus generally favour water with a pH in the roughly neutral-to-slightly-alkaline range and moderate to strong current, hugging riffles and runs rather than still pools.
No dedicated ecological survey of this particular species' habitat preferences was found; the description above reflects the general habitat of Nemacheilus stone loaches rather than confirmed, species-specific data. As with many single-locality Southeast Asian stream fish, its true range and habitat tolerances may be narrower — or different in detail — than the genus norm.
Feeding
As a Nemacheilus species, it is presumed to be a benthic micro-predator, working the streambed for small aquatic invertebrates and insect larvae rather than grazing algae or taking material from the water column. In the aquarium, related Nemacheilus species accept small live and frozen foods such as Daphnia, Artemia and bloodworm along with sinking prepared foods, and tend to ignore food that floats or drifts past mid-water.
No feeding study specific to Zhustura shuangjiangensis exists in the sources consulted; the diet described here is inferred from the genus and family rather than confirmed for this species.
Mating
No courtship or spawning behaviour has been documented for this species. Stone and brook loaches in Nemacheilidae are not known for elaborate pairing displays; where breeding has been observed in the family at all, fish typically come together over open gravel in fast-flowing water rather than forming pair bonds or defending territory.
Breeding
Nothing specific to Zhustura shuangjiangensis has been recorded. Going by its family, the expected pattern is that of a typical stone/brook loach: an egg-scatterer that releases eggs over gravel and among stones in fast-flowing water, with no parental care of eggs or fry. Nemacheilidae as a whole is rarely bred in captivity, and most species — this one very much included — have no confirmed aquarium spawning on record; this is honestly a case of "data sparse" rather than a fish with a known breeding routine.
In the aquarium
This species is not established in the aquarium trade and has no meaningful care record; nothing here should be read as tested advice. Anyone attempting to keep a Nemacheilus stone loach along these lines should follow the genus's general needs: cool-to-moderate, fast-moving, well-oxygenated water, a sand-or-gravel substrate, and strong filtration or powerhead-driven current to mimic a riffle. Being a scaleless or near-scaleless loach in the broader Cobitoidea tradition, it should be assumed sensitive to copper-based medications and full-strength treatments, so any dosing should start conservative. Given the total absence of a trade or husbandry record, the responsible position is to treat this as an unavailable, unstudied species rather than a recommended aquarium fish.
Conservation
Zhustura shuangjiangensis has not been assessed on the IUCN Red List and carries no conservation category; it is recorded here as Not Evaluated rather than assigned a guessed status. Known only from its type locality in the Xiaohei-jiang, Mekong basin, Yunnan, it fits the profile of many Nemacheilidae species — a narrow-range mountain-stream endemic that has never received a dedicated conservation assessment. There is no evidence in the sources consulted of an aquarium trade in this species, wild-collected or otherwise; any pressure on it would most plausibly come from general habitat disturbance in its home drainage rather than from ornamental collection.