Taxonomy & naming
Paraschistura ilamensis was formally described by Hadi Vatandoust and Soheil Eagderi in 2015, in the International Journal of Aquatic Biology, from specimens collected at Siahgav spring in Ilam province, Iran. The species epithet ilamensis simply marks that origin, naming it for Ilam, the province where it was found. It sits in the genus Paraschistura, one of several genera split in recent decades from the old, unwieldy catch-all Nemacheilus/Noemacheilus as ichthyologists worked through the stone-loach diversity of the Middle East and Central Asia — a process that continues to reshuffle names across the family.
The family Nemacheilidae is the largest of the loach families by species count, and Paraschistura is one of its western-Asian genera, distinct from the more familiar Schistura of Southeast Asia and the high-altitude Triplophysa of the Tibetan Plateau. As a species named only in 2015, P. ilamensis has not accumulated the synonymy or taxonomic history of older, better-studied loaches — the original combination is also the current one, and the Catalog of Fishes is the reference for confirming that this remains its valid name.
Morphology
The original description characterizes Paraschistura ilamensis as a stout-bodied stone loach with a distinctive emarginate (notched) caudal fin and a deep caudal peduncle. Its flanks carry seven to ten irregular, interrupted pale-brown bars over a lighter ground colour, a broken-barred pattern typical of many small nemacheilid stone loaches that helps them disappear against gravel and cobble. Mature males show a small moveable protuberance at the antero-ventral corner of the eye, a secondary sexual character used to help separate the sexes.
Like other members of its family it is a slim, elongate, nearly scaleless loach adapted for holding station in current — a body plan built for wedging into crevices and hugging the substrate rather than open swimming. FishBase records a maximum length of about 2 in standard length, making this a genuinely small fish. As with much of this species' biology, no further morphological detail — colour in life, sexual dimorphism beyond the eye protuberance, or barbel counts — has been published beyond the type description.
Habitat
Paraschistura ilamensis is known only from Siahgav spring, in the Tigris River drainage of Ilam province, western Iran (roughly 32°51'54"N, 47°42'2"E). This places it in one of the many small spring-fed tributary systems that feed the upper Tigris basin along the Iran–Iraq border region, a landscape of limestone springs and cool, clear watercourses distinct from the larger lowland rivers further downstream.
No published water-chemistry or temperature data accompany the description, but the genus and its spring habitat point to cool-to-moderate, clear, well-oxygenated, likely alkaline water typical of Zagros-region karst springs — the kind of habitat favoured by related Middle Eastern stone loaches such as Oxynoemacheilus and Paracobitis. Until direct measurements are published, the honest position is that the water parameters at Siahgav spring have not been documented in the sources available.
Feeding
No dietary study has been published for Paraschistura ilamensis specifically, but FishBase assigns it an estimated trophic level of about 2.8, consistent with a primarily invertivorous to omnivorous diet — the pattern typical of small nemacheilid stone loaches, which pick insect larvae, small crustaceans and other invertebrates off the streambed. As a benthopelagic species it most likely forages close to the bottom and among gravel and stones rather than in open water.
Given the total absence of aquarium or field-feeding observations for this species, any care-level feeding guidance would have to be extrapolated from its relatives rather than drawn from direct evidence — it is fair to expect a small live-and-frozen invertebrate feeder in the manner of other stone loaches, but that remains an inference, not a documented fact.
Mating
The original description notes a moveable protuberance at the antero-ventral eye corner in mature males, which is presumably a breeding or recognition character, but no observations of courtship, spawning behaviour, or seasonal timing have been published for this species. Nothing is known about how or when Siahgav spring's population reproduces in the wild.
Breeding
Paraschistura ilamensis has never been reported spawning in captivity, and there is no field account of its reproduction either — this is one of the many stone-and-brook loaches (family Nemacheilidae) about which almost nothing breeding-related has been documented. What can be said comes from the pattern shared across the genus and family: Nemacheilidae are egg-scatterers, broadcasting eggs over gravel and among stones in flowing water with no parental care, and they are rarely bred by hobbyists.
Given that P. ilamensis is a narrow-range endemic known from a single spring and essentially absent from the aquarium trade, it is realistic to say breeding.mode follows the family pattern by inference rather than direct observation: an egg-scatterer over gravel with no parental care, and — so far as any source records — never bred in the aquarium.
In the aquarium
Paraschistura ilamensis is not established in the aquarium hobby; none of the sources consulted describe it being kept or traded. As a small (around 2 in) stone loach from a cool, clear, flowing spring habitat, any hypothetical care would need to follow general nemacheilid stone-loach practice: a well-oxygenated tank with moderate-to-strong flow, a fine gravel or sand substrate with smooth stones to shelter among, and cooler, clean water rather than a warm, still community setup.
As with all nemacheilid loaches it is essentially scaleless and likely sensitive to copper and full-strength medications, a point worth flagging even in the absence of specific husbandry data for this species. Because it has not been reported in the trade, any specimens in circulation would almost certainly be wild-collected from its single known spring locality — a population small and localized enough that collection pressure could matter, even though no formal assessment exists to quantify it.
Conservation
Paraschistura ilamensis has not been evaluated by the IUCN Red List — it is recorded here as Not Evaluated (NE) rather than assigned a guessed status. This is unsurprising for a species described as recently as 2015 and known only from a single spring locality; many such narrow-range Middle Eastern stream endemics have not yet been formally assessed.
Species restricted to a single spring system in the Tigris basin are, by their nature, vulnerable to localized pressures — water extraction, agricultural runoff, and habitat modification are common threats to small spring habitats across western Iran and the wider region — but no study has documented the population trend or specific threats facing Siahgav spring itself. Until a formal assessment is carried out, its conservation status remains genuinely unknown rather than merely unpublicized.