Taxonomy & naming
Oxynoemacheilus chomanicus was described in 2014 by Kamangar, Prokofiev, Ghaderi and Nalbant in Zootaxa 3755(1), in a paper covering stone loaches of the Choman River system in Kurdistan. It was one of three new nemacheilid species reported from that drainage in the same study, reflecting how much cryptic diversity remains undescribed in the small stream loaches of the Tigris–Euphrates headwaters. The species has since been referenced in regional taxonomic work, including a 2024 paper by Kaya and colleagues in Zoosystematics and Evolution, and in a 2016 osteological study by Mafakheri describing its skeletal anatomy in detail.
It belongs to the genus Oxynoemacheilus, part of the family Nemacheilidae — the stone or brook loaches, now recognized as the largest family in the loach superfamily Cobitoidea after the wholesale splitting of the old wastebasket genera Nemacheilus and Noemacheilus. The Catalog of Fishes is the governing authority for the valid name, and it stands as Oxynoemacheilus chomanicus; no synonymy or reclassification affecting this species is noted here.
Morphology
As a member of Nemacheilidae, Oxynoemacheilus chomanicus has the elongate, subcylindrical body typical of stone loaches: a slender profile, a flattened belly suited to holding position on stream substrate, and a small mouth set beneath the snout, ringed with short barbels for probing gravel and detritus. Like other true loaches it lacks the erectile suborbital spine found in the botiid loaches (clown, yoyo, zebra loaches and kin) — that structure is a Botiidae feature, not a Nemacheilidae one.
The original description reported the type series — a holotype and several additional specimens — at roughly 1.5–2.5 in standard length, placing this among the small end of stone loaches. As in most Nemacheilidae, the skin carries very small, embedded scales or is functionally scaleless, making the fish, like its relatives, sensitive to medications and disease. Beyond the type-series measurements and the osteological detail captured in the 2016 skeletal study, detailed morphological description (coloration pattern, fin ray counts, precise diagnostic features separating it from congeners) is not available from the sources at hand; further detail should be sourced from the primary description before being added here.
Habitat
Oxynoemacheilus chomanicus is endemic to the Choman River system, a Tigris-drainage headwater in the Kurdistan region straddling Iran and Iraq. The type locality is the Choman River at Alut, Iraq, and the original survey also recorded stone loaches from the nearby Baneh, Boein and Shooei rivers in Iranian Kurdistan — all part of the same upper-Tigris hill drainage. This is classic stone-loach country: clear, fast-flowing, well-oxygenated streams running over rocky and gravel substrate in hilly to mountainous terrain.
Genus-level ecological work on Oxynoemacheilus describes these fish as benthic stream dwellers tied to flowing, rocky-bottomed water rather than still or heavily vegetated habitat. No specific published water-chemistry or temperature dataset for this species was found in the available sources; given its Kurdistan hill-stream setting, cool-to-moderate, well-aerated flowing water is a reasonable inference, but exact figures are not documented here and should not be invented.
Feeding
Genus-level research on Oxynoemacheilus feeding ecology describes these loaches as generalist benthic micro-predators, taking small invertebrates from fast-flowing rocky substrates, with aquatic insect larvae — particularly Diptera (true fly) larvae — forming the bulk of the diet. This fits the broader pattern for stone and brook loaches, which forage along the stream bed for insect larvae and small crustaceans rather than grazing algae or biofilm in the manner of hillstream loaches.
No species-specific dietary study of O. chomanicus itself was found; the feeding picture here is inferred from genus-level Oxynoemacheilus ecology rather than a study of this species. In an aquarium setting this profile would translate to small live and frozen foods and sinking pellets taken off the substrate, though the species has no documented aquarium history to confirm this.
Mating
No description of courtship or spawning behaviour specific to Oxynoemacheilus chomanicus was found in the available sources. Genus-level work on Oxynoemacheilus ecology notes breeding activity in late spring to early summer, with eggs deposited in rock crevices in flowing water — consistent with the broader Nemacheilidae pattern of egg-scattering over gravel and among stones in fast-flowing streams, without pairing behaviour or nest construction. Given the species is known only from wild collections with no aquarium history, sex differences and courtship for this species specifically remain undocumented.
Breeding
Oxynoemacheilus chomanicus has no documented aquarium breeding history, and none is expected: it is not in the hobby, and like the great majority of stone and brook loaches it would be an egg-scatterer with no parental care if bred at all. The genus-level pattern — eggs released over gravel or lodged in rock crevices in fast, oxygenated water, then left to develop unattended — is consistent with what little is recorded for Oxynoemacheilus generally.
This species should be treated as data-sparse for breeding specifically: there is no record of it being kept, spawned, or studied in captivity. Any breeding note beyond the genus-level egg-scattering pattern would be speculation rather than documented fact.
In the aquarium
Oxynoemacheilus chomanicus is not a fish of the aquarium trade. It is a range-restricted stream endemic known only from ichthyological survey and taxonomic description, with no record of import, captive husbandry, or hobbyist keeping. Nothing here should be read as care guidance from experience with the species itself.
That said, the broader stone-and-brook-loach group it belongs to offers a general template should material of this or a closely related Oxynoemacheilus ever reach hobbyists: cool-to-moderate, clean, fast-flowing, well-oxygenated water over a rocky or gravel substrate, strong filtration to replicate stream flow, and — because these are essentially scaleless fish — caution with copper-based and full-strength medications. As with any wild-collected stream endemic, sourcing would raise conservation questions given the species' narrow, single-drainage range.
Conservation
Oxynoemacheilus chomanicus 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. It is known only from the Choman River system and a small number of neighbouring rivers (Baneh, Boein, Shooei) in Iranian and Iraqi Kurdistan, all headwaters of the Tigris — a narrow, single-drainage range typical of many recently described nemacheilid loaches in this region.
Range-restricted stream endemics of the Iran–Iraq borderlands face pressures common to the region's hill streams — water abstraction, damming, and habitat alteration — but no species-specific population data, trend, or threat assessment exists for O. chomanicus. Its conservation status should be treated as genuinely unknown pending a formal Red List evaluation, rather than inferred from its narrow range alone.