Taxonomy & naming
Capoeta macrolepis belongs to the genus Capoeta, a western Palearctic group of cyprinids distributed from the Mediterranean basin through Anatolia, the Caucasus, the Middle East and into western and central Asia. The genus is well-supported as monophyletic in molecular phylogenetic studies, with Iranian diversity representing a significant component of its total species richness.
Phylogenetic work on Iranian Capoeta — including analyses that have drawn on specimens from the Kor River basin — places C. macrolepis within a clade of Iranian endemics. The species name macrolepis is from Greek makros (large) and lepis (scale), a reference to the notably large scales that distinguish this species from some congeners. The authority and original description details are not confirmed in the available literature for this account; only verified data from accessible sources are cited here.
The Catalog of Fishes (Eschmeyer, CAS) is the authority for the current valid combination Capoeta macrolepis. There is no documented history of the species being placed in the old wastebasket genus Barbus or Puntius; the name appears to have been established within Capoeta from the outset or was revalidated directly into it.
Morphology
Capoeta macrolepis is a moderately elongate, somewhat laterally compressed cyprinid with the general build typical of the genus: a fusiform body suited to flowing water, a subterminal to inferior mouth adapted for scraping, and a keratinised lower lip that acts as a hard edge for rasping biofilm and algae from rock surfaces. The large scales that give the species its name are a conspicuous feature, proportionally larger than those of several related Iranian Capoeta.
Size data for this species are sparse in the accessible literature. Related Iranian Capoeta span a broad range — some species remain under 6 in while others (such as C. umbla) can exceed 15.5 in total length — and C. macrolepis is expected to fall within the mid-range of the genus, though a verified maximum size figure is not available for this account. The body is typically silvery to bronze-grey, with the lower flanks paler; the fins lack the intense red or orange pigmentation seen in some congeners.
Habitat
Capoeta macrolepis is recorded from the Kor River basin in Fars Province, Iran — a river system draining the Zagros foothills before terminating in the endorheic Bakhtegan Lake system — and from the broader Tigris drainage. The Tange Boragh locality in the Kor basin is a documented collection site. These are temperate rivers characterised by clear to moderately turbid water, a predominantly rocky or gravelly substrate, and well-oxygenated conditions in the faster reaches.
As a member of Capoeta, the species is expected to favour riffles and runs with abundant periphyton growth on stable substrate — the habitat that supports its scraping feeding mode. The rivers of the Zagros region are subject to strong seasonal flow variation, with high discharge following winter rains and snowmelt and markedly reduced flow through the dry summer months. Water chemistry is typically neutral to alkaline and moderately to relatively hard, reflecting the calcium-rich geological substrate of the Fars region.
Feeding
Capoeta macrolepis, like all members of its genus, is primarily an aufwuchs feeder — a scraper of algae, diatoms and organic biofilm from hard substrates. The inferior, transverse mouth and hardened lower lip are functional adaptations for this feeding mode, allowing the fish to graze efficiently on epilithic algae in swift, clear river reaches where plant matter is otherwise scarce.
In addition to algae and biofilm, Capoeta species typically ingest small invertebrates, plant material and detritus incidentally while scraping. The digestive tract is long, as expected in a species relying heavily on nutritionally dilute plant material. In the aquarium, the feeding behaviour of scrapers can be met with algae wafers, spirulina-based sinking foods and regular vegetable matter, supplemented with small live or frozen invertebrates.
Mating
Like all members of the family Cyprinidae, Capoeta macrolepis is an egg-scattering, non-guarding spawner. There is no parental investment beyond the act of spawning itself. In Iranian river species of Capoeta, spawning is tied to seasonal hydrology: rising water temperatures in late winter and spring, combined with increased flow from snowmelt, appear to trigger reproductive activity. Males develop nuptial tubercles on the snout and dorsal scales ahead of the spawning season.
Courtship involves males pursuing gravid females through the current or over the substrate. Eggs and milt are released together, and the adhesive or semi-adhesive eggs settle among gravel or in crevices between rocks. No territory is defended, no nest is built, and adults disperse after spawning. This broadcast strategy is typical of large and mid-sized temperate riverine cyprinids that rely on high fecundity rather than parental care to achieve recruitment.
Breeding
Specific captive-breeding records for Capoeta macrolepis are not documented in the literature available for this account. Related Capoeta species and other temperate riverine cyprinids are generally challenging to breed in aquaria without replicating the seasonal temperature and photoperiod cycles that trigger spawning in the wild — a cool winter period followed by a gradual warm-up and increase in day length.
In principle, conditioning a group with high-quality varied foods and then gradually raising temperature while increasing flow and oxygenation would represent a reasonable approach consistent with the reproductive biology of the genus. Eggs would be expected to settle among coarse gravel and should be separated from the adults to prevent predation. Fertility, incubation period and larval development details are not available from confirmed sources for this species.
In the aquarium
Capoeta macrolepis is not an established aquarium fish in the hobby and is rarely if ever available in the ornamental trade. It is a species of scientific and specialist interest rather than a community aquarium subject. Those keeping related Capoeta species note that they require spacious tanks with strong filtration, high oxygenation and a meaningful current — conditions that replicate the fast-flowing rivers these fish inhabit in the wild.
A diet centred on algae-based foods (spirulina wafers, blanched vegetables, algae growth on décor rocks) is appropriate for the scraping feeding mode, supplemented with sinking pellets and occasional invertebrate foods. Water should be neutral to slightly alkaline and moderately hard, reflecting the limestone-influenced rivers of the Zagros region. Subtropical rather than fully tropical temperatures are appropriate, with a cooler period in winter advisable for long-term health and any breeding attempt. Tankmates, if kept, should be robust fish comfortable with fast water and strong flow.
Conservation
Capoeta macrolepis is endemic to a restricted range in south-western Iran, centred on the Kor River basin and connected Tigris tributaries. This narrow distribution makes it inherently vulnerable to catchment-level threats, and the Kor River system faces severe pressure from water abstraction for agriculture and urban supply, dam construction that alters flow regimes and blocks fish movement, and progressive habitat degradation from livestock grazing on riparian margins.
The endorheic Bakhtegan Lake, into which the Kor River historically drained, has experienced dramatic desiccation in recent decades due to upstream abstraction — a basin-wide change that has profound implications for the fish fauna dependent on the river system. No IUCN Red List assessment for Capoeta macrolepis was retrievable for this account; the conservation status of the species remains to be confirmed. Given the pattern of threat affecting narrowly endemic Iranian Capoeta, formal assessment and monitoring of this species are warranted.