Taxonomy & naming
Schistura macrotaenia was described by Yang in 1990. Molecular and morphological revision places it within the Schistura cincticauda species group, and it was formerly classified under the older, broader genus Nemacheilus as Nemacheilus macrotaenia — a combination still occasionally seen in older literature and databases. The Catalog of Fishes, the authority followed here, lists the current valid combination as Schistura macrotaenia, within the family Nemacheilidae.
Nemacheilidae is the largest of the loach families by species count, and its genus-level boundaries have been repeatedly reshuffled as ichthyologists split the old catch-all genera Nemacheilus and Noemacheilus into narrower, better-supported groups — Schistura, Triplophysa, Barbatula and others among them. S. macrotaenia's placement in Schistura reflects that ongoing revision rather than a settled, decades-old classification.
Morphology
As a member of Schistura, this is a small, elongate, cylindrical loach built for holding position on stream bottoms rather than for open swimming. Like other nemacheilids it is a true loach with a benthic body plan: a flattened underside, a small subterminal mouth, and barbels around the mouth for feeling out food on and under stones. Many Schistura, including species in the same cincticauda group, carry the erectile suborbital spine typical of the broader loach group and the near-scaleless or finely-scaled skin that makes the family sensitive to medication — features reasonably inferred here from its genus and relatives, though no size or detailed morphological description specific to S. macrotaenia has been located.
No maximum length or other precise morphometric data for this species were found in the sources consulted. Given the small size typical of Schistura generally, and of the related, better-documented S. robertsi in particular, it is very likely a compact fish measured in a few centimetres rather than a large one — but that figure is not stated for this species and should not be assumed as fact.
Habitat
Schistura macrotaenia is recorded from the Tengtiao Jiang River drainage in Yunnan Province, southwestern China, and may also occur in adjacent drainages of northern Vietnam. FishBase classifies it as a freshwater, benthopelagic species of temperate Asia — language that points to a cool-to-temperate mountain or foothill stream environment rather than a warm lowland one, consistent with its Yunnan type locality in the uplands bordering the Tibetan plateau region.
No published water-chemistry data (temperature, pH, hardness) specific to this species were found. Nemacheilid stone loaches from this part of continental Asia typically inhabit clear, fast-flowing, well-oxygenated streams over gravel, cobble and sand, and that general habitat picture is the best-supported inference here — but exact figures for S. macrotaenia are not available and are not fabricated in the facts below.
Feeding
No feeding data specific to Schistura macrotaenia were found in the sources consulted. Related Schistura, including S. robertsi, are described as micro-predators that work the substrate of clear hill streams for small invertebrates — insect larvae and small crustaceans in particular — rather than grazing algae or taking flake food from the water column.
On that genus-level basis, S. macrotaenia is most plausibly a similar bottom-foraging micro-predator, but this is an inference from its relatives rather than a documented fact for the species itself, and it is presented here with that caveat.
Mating
No information on sexing, courtship or spawning behaviour specific to Schistura macrotaenia was found. Nothing in the cached sources describes dimorphism, breeding tubercles, or any seasonal spawning migration for this species, and none should be assumed.
For the genus generally — and for related hillstream and stone loaches — egg-scattering with no courtship ritual beyond release into moving water is the typical pattern, but that too is a genus-level inference rather than a documented observation of this species.
Breeding
Schistura macrotaenia has, so far as the available sources show, never been documented breeding in the aquarium, and no wild spawning observations were found either. This fits the pattern across Nemacheilidae: stone and brook loaches are presumed egg-scatterers that release eggs over gravel or among stones in fast water, with no parental care, but the great majority — including range-restricted, poorly-studied species like this one — are simply not bred by hobbyists and are rarely if ever studied in captivity.
Data for this species specifically is sparse to the point of absence. The safest statement is the honest one: breeding biology is unknown to this account, and the mode given in the facts below (egg-scatterer, no parental care) is a genus-level default inferred from Schistura and Nemacheilidae generally, not a confirmed report for S. macrotaenia.
In the aquarium
Schistura macrotaenia is not established as an aquarium species in the sources reviewed, and no keeping reports specific to it were found. It should not be assumed to be in the hobby at all; if it does appear, it would come from wild collection out of the Tengtiao Jiang drainage rather than any captive-breeding program.
What can be said with reasonable confidence, drawing on its temperate-Asia, benthopelagic classification and its placement among hillstream-adjacent Schistura relatives, is the general care profile that applies across the group: cool-to-moderate, clean, fast-flowing, well-oxygenated water over a hard substrate, and — as with essentially all nemacheilid and other true loaches — a near-scaleless body that calls for caution with copper-based and full-strength medications. A keeper who did encounter this species should treat it as a specialist, low-information fish and research its actual wild conditions rather than defaulting to generic tropical-community care.
Conservation
Schistura macrotaenia is listed by the IUCN Red List as Data Deficient, assessed on 11 August 2010. That status reflects a genuine lack of information — on population size, trend, precise range extent and threats — rather than any finding of security or of risk. Data Deficient is common among narrow-range Nemacheilidae, many of which are known from a single river system or a handful of collection records.
Its known range is limited to the Tengtiao Jiang River drainage in Yunnan, China, with a possible extension into northern Vietnam, so any localized pressure on that drainage — damming, pollution, sedimentation or water extraction — would be worth monitoring even though no specific threat has been documented for this species. There is no evidence in the available sources of a significant aquarium trade in this species, so trade pressure is not identified as a concern here.