Taxonomy & naming
Labeobarbus macrolepidotus was first described by the French ichthyologist Jacques Pellegrin in 1928 under the combination Varicorhinus macrolepidotus. The parenthetical authority in the current name — (Pellegrin, 1928) — marks its subsequent transfer to Labeobarbus. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) recognises Labeobarbus macrolepidotus as the valid name.
The genus Labeobarbus encompasses the large African barbs sometimes called yellowfish or big barbs — a diverse group of cyprinids spanning highland and lowland rivers across sub-Saharan Africa. The Congo Basin holds a particularly diverse assemblage of Labeobarbus species, and a number of congeners occupy the same river system as macrolepidotus, including the closely related L. semireticulatus, against which the larger scales of macrolepidotus were originally noted in the original description. The FishBase identifier for this species is 11638.
Morphology
As its name signals, Labeobarbus macrolepidotus is characterised by conspicuously large scales relative to body length — a feature that distinguishes it from the co-occurring L. semireticulatus and provided the basis for Pellegrin's species epithet. It is a large-bodied barb with the fusiform, robust build typical of the genus: a deep, laterally compressed torso, a subterminal mouth suited for bottom or mid-water feeding, and a forked caudal fin.
Within the Labeobarbus genus, Congo Basin species range broadly in size, with congeners recorded at 2.5–10 in SL in upper Congo tributaries. Detailed meristic data for macrolepidotus specifically are limited in the available literature, but the species fits within the larger end of the African barb spectrum. Colouration in life is not well documented in the accessible sources.
Habitat
Labeobarbus macrolepidotus is recorded from the lower Congo River and the Kasai River, a major southern tributary of the Congo, within the Democratic Republic of Congo and Angola. The Congo Basin is a vast tropical lowland system draining roughly 3.7 million km², characterised by warm, nutrient-rich, moderately turbid waters in its lower reaches, transitioning to cooler, faster highland streams in the upper basin.
Congeners studied in upper Congo tributaries such as the Luhoho Basin occur in tropical rainforest streams at elevations of roughly 700–1,0 ft, where water is cool and well-oxygenated. The lower Congo and Kasai, where macrolepidotus is primarily recorded, are larger, warmer lowland rivers. Like other Labeobarbus, the species is likely associated with flowing, well-oxygenated river habitat rather than standing or stagnant water.
Feeding
The genus Labeobarbus shows two broad feeding strategies: a herbivorous chiselmouth form that scrapes epilithic algae and biofilm from hard substrates, and an insectivorous rubberlip form that gleans aquatic invertebrates. The specific feeding guild of L. macrolepidotus has not been recorded in the sources consulted, but the subterminal mouth morphology common to many Labeobarbus is consistent with a benthos-associated diet incorporating plant matter, algae, detritus and invertebrates.
In the Congo Basin, large barbs typically exploit the seasonal pulse of invertebrate productivity and plant material that accompanies fluctuating river levels. In the aquarium, Labeobarbus are best offered a varied diet of quality pellets, blanched vegetables and occasional protein items such as bloodworm or earthworm to reflect the breadth of their natural diet.
Mating
Labeobarbus macrolepidotus, like all barbs, is an egg-scattering, non-guarding spawner. No nest is built and no parental care is provided at any stage. Spawning in large river barbs of this kind is typically seasonal, cued by rising water levels and temperature shifts that accompany the annual flood pulse of the Congo Basin. A driving male pursues a gravid female through open water or over the substrate, and eggs and milt are released together in a brief broadcast event.
There is no pair bond, no territory held beyond the immediate moment of courtship, and no egg or fry guarding. Adults commonly consume their own eggs if they encounter them after spawning. The precise spawning sites preferred by macrolepidotus in the wild — whether over gravel runs, flooded vegetation, or open river margins — are not documented in the available literature.
Breeding
Captive breeding of Labeobarbus macrolepidotus has not been documented in the accessible hobbyist or scientific literature. Large African barbs of this genus are rarely kept in the aquarium trade and are consequently almost unknown in captive reproduction. General principles applicable to large river barbs suggest that a significant tank volume, conditioning on a high-quality and varied diet, and a simulated seasonal cue — a gradual temperature shift or increased water flow — would be necessary preconditions.
Eggs would be scattered over the substrate or among coarse gravel without any parental attention, and adults should be separated from the spawning site promptly to prevent egg predation. Given the size that macrolepidotus attains, dedicated spawning facilities beyond the reach of standard aquarium setups would be required. Data on clutch size, incubation duration and larval development are not available for this species.
In the aquarium
Labeobarbus macrolepidotus is not an aquarium trade species in any meaningful sense. Large African barbs of the genus Labeobarbus are virtually absent from the hobby, being large-bodied fish that require very substantial aquaria and are not bred commercially. The species is native to major Congo Basin rivers and is primarily of interest to public aquaria with the facilities to house large cyprinids, and to ichthyologists and conservation biologists studying Congo Basin biodiversity.
For hobbyists interested in the genus, smaller African Labeobarbus — where legally and sustainably available — would be far more tractable. The species should not be purchased on impulse; responsible acquisition of any large barb requires detailed advance preparation, appropriate filtration and space, and an understanding of the fish's size at maturity.
Conservation
Labeobarbus macrolepidotus was assessed by the IUCN in 2022 and placed in the Least Concern category, reflecting an adequately wide distribution within the Congo River system and no evidence of major population decline. The Congo Basin as a whole retains large areas of relatively intact forest and river habitat compared with many other major African river systems, which provides some resilience for its fish fauna.
Nonetheless, the lower Congo and Kasai rivers face growing pressures from artisanal and commercial fishing, mining activity — including cobalt and coltan extraction in eastern DRC — and expanding human settlement along river corridors. Large-bodied fish are especially vulnerable to overharvest because they take years to reach reproductive maturity and are targeted preferentially by subsistence fisheries. Ongoing monitoring of the Congo Basin's large cyprinid fauna will be important as infrastructure development increases access to previously remote watersheds.