Taxonomy & naming
Physoschistura tigrinum was described by Lokeshwor and Vishwanath in 2012 from the Changa River, part of the Chindwin drainage in Manipur, India, with the holotype (MUMF 11051, a 3 in SL male) deposited at Manipur University. The species belongs to Nemacheilidae, the stone or brook loaches, a family that has been repeatedly reshuffled as the old catch-all genera Nemacheilus and Noemacheilus were broken apart — Physoschistura, erected by Bănărescu and Nalbant, is one of the resulting genera for small barred stream loaches of the eastern Himalaya and Indo-Burma region.
Catalog of Fishes, the standing authority for valid names, records that the species was subsequently moved by Kottelat (2018) into the genus Mustura, giving the combination Mustura tigrina. This article follows the original combination, Physoschistura tigrinum, as the genus most consistently used to describe the species. The specific epithet tigrinum is Latin for "tiger-like," chosen for the irregular dark bars running down the flanks.
Morphology
This is a small, slender-bodied stream loach reaching about 3 in SL. The body carries 12–14 irregular light reddish-brown bars along the sides and 5–6 reddish-brown saddles across the back, the tiger-stripe pattern that gives the species its name. The lateral line is complete, running the full length of the body with 90–94 pores, and the caudal fin is forked, with nine plus eight branched rays; the dorsal fin has nine and a half branched rays.
Like other nemacheilids it almost certainly carries the family's erectile suborbital spine — a small, hinged spine tucked in a groove below the eye that can be flicked out defensively — and the near-scaleless, delicate skin typical of the group, though neither trait was specifically described for this species in the sources available. That near-naked skin is the reason true loaches as a group are handled carefully around medications; see In the aquarium.
Habitat
Physoschistura tigrinum is known only from its type locality, the Changa River, a tributary within the Chindwin drainage in Manipur, north-east India (roughly 25°12′N, 94°31′E). The Chindwin is a major tributary of the Irrawaddy system, and the stretch of stream the species was collected from is typical stone-loach water: a clear, flowing, rocky-bedded hill stream in the tropical Asian freshwater zone.
No published water-chemistry or temperature data are available for this specific stream reach, but the genus and family as a whole are fish of cool-to-warm, well-oxygenated, fast-flowing water over gravel and stone, not still or blackwater habitat. Given the elevation and hill-stream character of its known range, moderate rather than tropically warm temperatures are the reasonable expectation, though this should be treated as an inference from the family's habits rather than a measured figure.
Feeding
No diet data have been published for Physoschistura tigrinum specifically. As with other Nemacheilidae, it is reasonable to expect it forages as a bottom-dwelling micro-predator, picking small invertebrates — aquatic insect larvae, worms and tiny crustaceans — from among the gravel and stones of its home stream, in the manner typical of the family.
In the near-total absence of aquarium-keeping records for this species, there is no confirmed account of its feeding behaviour in captivity. Any keeper working with genuinely wild-collected stock should expect a fish that wants small live or frozen foods delivered at the substrate, following the pattern documented for its better-known nemacheilid relatives, rather than assume it will take flake readily.
Mating
Nothing has been published on sexual dimorphism, courtship or spawning behaviour in Physoschistura tigrinum. The species is known from the original type series collected in 2012 and has not, as far as the available sources show, been kept, observed or bred in captivity since.
For Nemacheilidae generally, spawning is understood to occur in fast, well-oxygenated water with no courtship display beyond simple pairing, and this species should be assumed to follow that pattern until directly observed — but that assumption should not be mistaken for documented fact.
Breeding
Data are sparse to nonexistent. Stone and brook loaches in Nemacheilidae are, as a family, egg-scatterers: ripe adults release eggs over gravel or among stones in fast-flowing water, with no parental care afterward, and the great majority of species — this one very much included — are rarely or never bred in the home aquarium.
There is no record of Physoschistura tigrinum having been spawned in captivity. Its status as a single-river endemic known mainly from its original description, with no aquarium-trade history to speak of, makes any statement about hobby breeding speculative; the honest summary is that this is not a fish anyone has documented breeding outside its native stream.
In the aquarium
Physoschistura tigrinum has essentially no aquarium-keeping track record; it is not established in the ornamental trade, and this profile should be read as inference from its family rather than as tested care advice. Like other nemacheilid stone loaches, its near-scaleless skin means it should be assumed sensitive to copper-based medications and full-strength treatments generally, warranting the same caution — half-doses, gentle products, close observation — used for its better-documented relatives.
A keeper attempting this species, were wild-collected stock ever available, should plan for cool-to-moderate, clean, fast-flowing, highly oxygenated water over a gravel or stone substrate, mimicking the hill-stream conditions of the Chindwin drainage, rather than a warm, still community tank. Given the total absence of husbandry literature, anyone working with it should treat every parameter as provisional and err toward the conditions of a clear Indo-Burmese hill stream.
Conservation
Physoschistura tigrinum has not been evaluated by the IUCN Red List, so it carries no formal conservation category; that gap is common among recently described, single-locality Nemacheilidae and should be read as an absence of assessment, not as evidence of security.
As a species known only from the Changa River in the Chindwin drainage of Manipur, it is by definition a narrow-range endemic, and stream endemics of this kind are inherently vulnerable to habitat degradation, siltation and water diversion even in the absence of a formal Red List review. There is no evidence in the available sources of an aquarium trade in this species, wild-collected or otherwise.