Taxonomy & naming
Capoeta shajariani was formally described in 2017 by Jouladeh-Roudbar, Eagderi, Murillo-Ramos, Ghanavi and Doadrio in the journal FishTaxa (volume 2, issue 3). The holotype, IMNRF-UT 1107-21, was collected from the Gamasiab River near Doab Village, Tigris basin, Hamedan Province, Iran (approximately 34°22′N, 47°54′E). The species is placed in the genus Capoeta, a diverse and largely western-Asian group of cyprinids whose members share a characteristic scraping dentition adapted to grazing epilithic algae from rocky substrates.
The genus Capoeta was long divided across the old, broadly defined genus Barbus before phylogenetic and morphological revisions consolidated the western-Asian algae-scrapers into their own lineage. The Catalog of Fishes recognises Capoeta as the valid genus for this species. C. shajariani is one of several Capoeta described from the Iranian Tigris tributaries in recent years, reflecting ongoing taxonomic work in a region whose fish fauna remains incompletely documented.
Morphology
Capoeta shajariani reaches a maximum recorded standard length of about 8 in (males or unsexed). Like other members of the genus it has a somewhat elongate, fusiform body suited to life in flowing water, a subterminal or inferior mouth with a hardened, scraping lower lip characteristic of algae-feeding Capoeta, and the relatively stout build typical of benthic rheophiles.
Data on colouration and detailed external morphology in the published literature are limited; the species is presumed to share the general Capoeta gestalt of a silvery to olive-grey body with dusky or darkened scale margins and no bold pattern, consistent with a cryptic riverine fish. Sexual dimorphism has not been characterised in detail for this species.
Habitat
Capoeta shajariani inhabits fast-flowing, clear rivers with rock and bedrock substrates in the Zagros foothills and mountains of western Iran, within the broader Tigris drainage. Habitat studies in the Dinorab River (a Karkheh drainage tributary in Kermanshah Province, where related Capoeta occur) recorded water temperatures of 64–66 °F, pH 7.22–7.44, and a total dissolved solids of 580–610 mg/L with electrical conductivity of 290–310 µS/cm — characteristically cool, neutral to mildly alkaline and moderately mineralised upland river water.
Channel dimensions at study sites ran to depths of 10–12 in and widths of 20–24 ft, with moderate current velocities around 1 ft/s over bedrock and coarse substrate (median bedrock clast around 2 in). These are rheophilic, well-oxygenated habitats where epilithic algal mats can develop on exposed rock surfaces — precisely the microhabitat the scraping Capoeta guild exploits.
The type locality is the Gamasiab River near Doab Village in Hamedan Province; the species is also recorded from the Dinevar, Qarasu, Khoram (Khoram Abad), Aran and Sarab-e Maran rivers, all within the Tigris drainage in Iran.
Feeding
Capoeta shajariani is a rheophilic benthic alga-scraper, a feeding guild shared across the genus Capoeta. The hardened, subterminal mouth with its scraping lip is an adaptation for rasping epilithic algae, biofilm and periphyton from the surfaces of rocks and bedrock in fast-flowing river reaches. This is the dominant food source in the well-lit, fast-flowing stretches these fish inhabit.
Like other Capoeta, it likely supplements its diet with organic detritus, fine plant matter and small invertebrates associated with the biofilm layer, but algal grazing is the primary trophic strategy. In clear, rocky mountain rivers of the Zagros, this niche positions it as an important processor of primary production on hard substrates.
Mating
No specific reproductive observations have been published for Capoeta shajariani. It is a member of the cyprinid family and, in common with the overwhelming majority of barbs and their relatives, is presumed to be an egg-scattering, non-guarding spawner. In Capoeta and related western-Asian cyprinids, spawning typically occurs seasonally, often in spring when snowmelt raises water levels and temperatures shift, stimulating upstream movement toward shallow gravel reaches where eggs are broadcast.
There is no evidence of nest construction, parental guarding or any form of brood care in any Capoeta species. During courtship a male pursues a gravid female over gravel or bedrock substrate, and eggs and milt are released together without further investment from either parent.
Breeding
Consistent with the egg-scattering mode universal in cyprinids, Capoeta shajariani deposits adhesive eggs over gravel or rocky substrate during seasonal spawning events. No guarding or parental care follows; eggs are left to develop in the interstices of the substrate or to drift downstream, and adults do not associate with their eggs or fry.
No aquarium breeding accounts exist for this species. It has not entered the ornamental trade in any meaningful way, and all known individuals are wild-caught specimens collected for scientific study. Reproductive details such as fecundity, incubation time and early larval development remain undescribed.
In the aquarium
Capoeta shajariani is not an aquarium fish. It is an endemic, scientifically described species known only from a small number of Iranian river systems and has not entered the ornamental trade. There are no aquarium-keeping accounts for this species.
For those interested in the Capoeta guild more broadly, the genus's scraping ecology and preference for cool, well-oxygenated, alkaline water over rock substrates would make suitable aquarium conditions challenging to replicate — requiring large tanks with strong, clean flow, hard and neutral-to-alkaline water chemistry, and abundant algae-coated rock surfaces rather than typical planted or tropical setups. This fish belongs to rivers, not display tanks.
Conservation
Capoeta shajariani has not been evaluated by the IUCN Red List and carries a status of Not Evaluated (NE). As an Iranian endemic known from only a handful of tributaries within the Tigris drainage — the Gamasiab, Dinevar, Qarasu, Khoram Abad, Aran and Sarab-e Maran rivers — its range is inherently limited, making it potentially vulnerable to localised threats.
The rivers of the Zagros and the broader Iranian Tigris system face increasing pressure from water extraction for agriculture and urban use, damming for irrigation and hydropower, and pollution from agricultural runoff and domestic wastewater. Many Iranian endemic cyprinids with similarly restricted ranges have been assessed as threatened or near-threatened when evaluated. Formal IUCN assessment of C. shajariani is warranted given its small known range and the documented pressures on its habitat.