Taxonomy & naming
Capoeta razii was formally described by Jouladeh-Roudbar, Eagderi, Ghanavi and Doadrio in 2017, published in ZooKeys. The species was diagnosed from the Kheyroud River (type locality: 36°36'35"N, 51°33'45"E), Chalos, Mazandaran Province, in the southern Caspian Sea basin of northern Iran. The holotype measures 5.5 in SL, and paratypes span 3.5–7.5 in SL.
The genus Capoeta is a well-defined group of scraping cyprinids distributed across the Middle East, Anatolia, the Caucasus, and the southern Caspian drainages. Capoeta razii is distinguished from congeners — including the more widespread C. capoeta and C. damascina — by a combination of meristic characters: one pair of barbels, a pre-dorsal length roughly equal to the post-dorsal length, a maxillary barbel shorter than the eye diameter, and 46–54 lateral-line scales with 7–9 scales between the dorsal-fin origin and the lateral line and 6–7 scales between the anal-fin origin and the lateral line. The Catalog of Fishes (Eschmeyer, CAS) is the authority for valid names in this family.
Morphology
Capoeta razii reaches a maximum recorded total length of 8 in, placing it among the medium-sized members of its genus. The body form is that of a typical scraping barb — moderately elongate, somewhat compressed, with a slightly inferior mouth suited to rasping algae and biofilm from hard substrates.
The species bears a single pair of barbels; the maxillary barbel is notably short, not reaching the diameter of the eye. Scale counts of 46–54 along the lateral line are characteristic, as is the roughly symmetrical placement of the dorsal fin relative to the body midpoint (pre-dorsal length approximately equalling post-dorsal length). As with all Capoeta, the lower lip edge is hardened and keratinised — a scraping adaptation — setting the genus apart from many other Palaearctic cyprinids.
Habitat
The Kheyroud River system, where the species was described, is a narrow, fast-flowing stream — 10–46 ft wide and roughly 3 ft deep — draining a deciduous forest landscape in the Alborz foothills of Mazandaran Province. The substrate is cobble and gravel, and the current is medium to fast and well-oxygenated. These cool, clear, upland-draining rivers are typical of Capoeta habitat in the southern Caspian region.
Additional habitat data from the Zarem stream (a Tajan River tributary, also in the southern Caspian basin) show that C. razii favours sections with larger stone diameter, relatively warmer microhabitat temperatures within the catchment, and lower flow velocity at the microsite level — consistent with a fish that grips substrate to graze, seeking shelter from the fastest main-channel currents while remaining in well-oxygenated water. The species appears most abundant within its native drainages and is not recorded outside Iran.
Feeding
Capoeta razii is an aufwuchs feeder — a periphyton and algae scraper — consistent with the trophic habit shared across the genus Capoeta. The hardened lower lip allows it to rasp biofilm, filamentous algae, and associated diatoms and invertebrates from rock and cobble surfaces.
In the aquarium, aufwuchs-feeding cyprinids of this type accept sinking algae wafers and spirulina-based foods, and benefit from surfaces bearing natural algae growth. Small invertebrate matter, such as frozen bloodworm or Daphnia, is also taken; a diet weighted toward plant and algae material better reflects the species' digestive physiology.
Mating
Like all barbs, Capoeta razii is an egg-scattering, non-guarding spawner. No nest is built, no territory is maintained beyond transient courtship activity, and the species provides no parental care. Spawning behaviour in the genus typically involves a male driving a gravid female over the substrate or among any available vegetation, with eggs and milt released together during brief contact.
In the wild, spawning in southern Caspian barbs is likely tied to seasonal warming in spring or early summer, when snowmelt-fed rivers reach temperatures suitable for gonadal activity. The adhesive eggs fall among cobbles or onto the substrate, where they develop without any attention from the adults.
Breeding
Capoeta razii has not been established in the aquarium trade and there are no published captive-breeding accounts for this species. Given its biology as an egg-scattering barb, breeding methodology would follow the general pattern used for similar Palaearctic and western Asian cyprinids: a cool-to-moderate temperature range, clean well-oxygenated water, a substrate of gravel or smooth stones over which the fish can scatter eggs, and removal of adults after spawning to prevent egg predation.
The species' relatively large adult size (up to ~8 in TL) and its origin in cool, fast-flowing mountain streams suggest it would require a spacious aquarium with strong filtration and flow, analogous to the requirements for temperate barbs and small barbels. No data on fecundity, incubation period, or larval development are available in the literature reviewed.
In the aquarium
Capoeta razii is not an established aquarium species and is unlikely to be encountered in the ornamental trade. It is a scientifically described endemic of limited range known primarily from ichthyological surveys and the original species description, and its care requirements have not been documented in the hobby literature.
For context: closely related Capoeta species that have occasionally been maintained by specialist keepers do best in cool, hard, well-oxygenated water with strong flow and a rocky substrate, a diet anchored by algae-based foods, and tankmates suited to fast-water temperate conditions. Any aquarist obtaining specimens of Capoeta from Iranian or Caucasian rivers should treat them as cool-water fish requiring conditions quite different from the tropical barbs of South and Southeast Asia.
Conservation
Capoeta razii has not been formally assessed by the IUCN Red List. As a narrow-range endemic known from a small number of tributaries within the southern Caspian Sea basin of northern Iran, it is potentially vulnerable to the pressures that threaten small-basin cyprinids throughout the Middle East and Caucasus region: water abstraction for agriculture and urban use, damming of rivers, siltation, pollution, and the introduction of invasive species.
The southern Caspian drainages of Mazandaran Province host a distinctive ichthyofauna with a high degree of endemism, and several species in this system remain formally unevaluated despite restricted ranges. Baseline population surveys and monitoring of the Kheyroud and Tajan river systems would be a prerequisite for any future conservation assessment of C. razii.