Taxonomy & naming
Yunnanilus tigerivinus was described by Li and Duan in 1999, originally published in the Journal of Yunnan Agricultural University as a newly recognised aquarium fish species from Yunnan. It sits in the genus Yunnanilus, a large assemblage of small nemacheilid loaches endemic to southern China and adjacent parts of Southeast Asia, most named for the Yunnan plateau where the genus is at its most diverse.
The taxonomic standing of this species is not entirely settled: some authorities consider Yunnanilus tigerivinus a junior synonym of Yunnanilus pleurotaenia, a more widely documented species from the same region, rather than a distinct species in its own right. Pending a fuller revision of the genus, this article follows the name as it stands and keeps the species separate, but that uncertainty is worth flagging rather than papering over. The family placement is Nemacheilidae — the stone or brook loaches, split many years ago from the old, broad Cobitidae — within the loach superfamily Cobitoidea.
Morphology
Like other members of its genus, Yunnanilus tigerivinus is a small, slender, elongate loach with a rounded body, a pointed snout bearing barbels around the mouth, and the near-scaleless, thin skin typical of Nemacheilidae. No dedicated size or colour-pattern description is available in the sources consulted here, so specific measurements and pattern details are not asserted; the name "tigerivinus" hints at a striped or barred pattern, in keeping with many of its Yunnanilus relatives, but this should be read as suggestive rather than confirmed.
As in most stone loaches, an erectile suborbital spine is present below the eye — a defensive feature shared across Cobitoidea — and the body lacks the heavy, overlapping scales seen in many other fish groups, leaving the skin sensitive to handling and to strong medications. Data on this particular species' morphology beyond the original description is sparse.
Habitat
The type locality for Yunnanilus tigerivinus is the opening of an underground channel in a suburb of Kunming, Yunnan Province, in southern China — a spring-fed or cave-associated stream outlet rather than an open river. This kind of habitat is typical of karst country in Yunnan, where streams disappear underground and re-emerge, often carrying cool, clear, mineral-rich water.
The species is treated as endemic to China, and specifically to this narrow area around Kunming. Nothing in the available sources describes its full range beyond the type locality, so its habitat should be considered narrowly known: a single documented population associated with a spring or underground watercourse, consistent with the cool, clear, well-oxygenated conditions favoured by stone loaches generally.
Feeding
No diet information specific to Yunnanilus tigerivinus was found in the sources consulted. Based on the well-documented feeding ecology of the genus Yunnanilus and Nemacheilidae generally, this species is best assumed to be a benthic micro-predator, picking small invertebrates, insect larvae and other tiny prey items off the streambed and among stones in cool, fast-flowing water.
In the aquarium, related Yunnanilus species are kept on a diet of small live and frozen foods — Daphnia, Moina, Artemia nauplii and microworms — and may largely ignore dry flake. In the absence of species-specific data, the same approach is the sensible starting point for Yunnanilus tigerivinus, offered as a reasonable inference from its genus rather than a confirmed fact about this fish.
Mating
No courtship or spawning behaviour has been documented specifically for Yunnanilus tigerivinus. In the wider genus, Yunnanilus species are reported to be highly gregarious, schooling loaches, and spawning in related species involves the male approaching and mouthing the area around the female's cloaca before eggs are released — a loose, unstructured pairing rather than a fixed courtship display or pair bond.
Without dimorphism data for this species, sexes cannot reliably be distinguished, and nothing can honestly be said about seasonal or environmental spawning triggers specific to Yunnanilus tigerivinus. This is a case where the responsible course is to note that data is sparse rather than to extrapolate confidently.
Breeding
As with most stone and brook loaches, Yunnanilus tigerivinus is an egg-scatterer with no parental care, and it is rarely, if ever, bred deliberately in home aquaria. In related Yunnanilus species that have been spawned in captivity, eggs are scattered over gravel or fine substrate in flowing water and hatch within about a day at warm temperatures, with fry needing infusoria-type foods before graduating to larger fare; dense planting is important for fry survival in a community setting.
No breeding account exists for Yunnanilus tigerivinus itself in the sources reviewed here. Given how narrowly known the species is — a single type locality and taxonomic uncertainty over its validity — captive breeding reports, if any exist, have not surfaced in the literature consulted, and this should be treated as an essentially unbred species in the hobby.
In the aquarium
Yunnanilus tigerivinus is not established in the aquarium trade under this name, and species-specific husbandry data does not exist in the sources available here. As a general guide drawn from the genus, Yunnanilus loaches do best in cool-to-mild, well-oxygenated water with some flow, a fine soft substrate, and plenty of stone or gravel cover to mimic a clear stream bed; they are gregarious and should be kept in a group rather than alone or in pairs.
Being near-scaleless like other nemacheilids, any Yunnanilus should be treated cautiously with medications and never dosed with copper-based treatments at full strength. Given the taxonomic uncertainty around this species and the complete absence of confirmed aquarium records, a prospective keeper should treat any fish sold under this name with real caution about its true identity and needs.
Conservation
Yunnanilus tigerivinus has not been assessed on the IUCN Red List and is recorded here as Not Evaluated. It is known only from a single type locality — an underground stream outlet near Kunming, Yunnan — making it, at best, a narrow-range endemic, and its status is further complicated by the possibility that it is a synonym of Yunnanilus pleurotaenia rather than a distinct species.
Karst spring and underground-stream habitats in the Kunming area, like much of Yunnan's freshwater systems, face pressure from urban expansion and groundwater extraction, though no documented population trend exists for this species specifically. In the absence of a formal assessment or population data, the honest summary is that this is a data-sparse, narrow-range fish about which too little is known to characterise its conservation status with any confidence.