Taxonomy & naming
Micralestes schelly was formally described by Melanie L. J. Stiassny and Victor Mamonekene in 2007, in a revision of the Micralestes of the lower Congo River published in Zootaxa. The revision simultaneously reviewed all Micralestes then known from the lower Congo system and established that the fauna included at least six species, several of them restricted to specific sections of the rapids corridor. Catalog of Fishes records the valid name as Micralestes schelly Stiassny & Mamonekene, 2007; as a new combination was not needed, the authority is unparenthesised.
The genus Micralestes belongs to the family Alestidae, the African tetras — a family restricted to sub-Saharan Africa and the Nile drainage, encompassing well-known hobby fishes such as the Congo tetra (Phenacogrammus interruptus) and the African moon tetra (Bathyaethiops caudomaculatus) alongside many lesser-known species. Within Alestidae, Micralestes is a genus of small, slender fishes widely distributed across savanna and forest rivers of sub-Saharan Africa; the lower Congo populations represent a localised species flock shaped by the extraordinary hydraulic and geographic isolation of the gorge system.
The species epithet honours Robert C. Schelly, an American ichthyologist at the American Museum of Natural History (AMNH) who collected the type series. Naming a species after a collector who contributed significantly to its discovery is a longstanding ichthyological tradition, and the dedication acknowledges the fieldwork behind any lower Congo collection — surveys in that reach require specialised logistics and access to one of the most powerful rivers in the world.
Morphology
Micralestes schelly is a small, slender-bodied alestid reaching a maximum recorded standard length of 2 in (approximately 1.9 in) in the male or unsexed specimens reported by FishBase. Like other Micralestes, the body plan is elongate and compressed, adapted for life in mid-water rather than the benthic or surface extremes. The original description provides meristic and morphometric characters that assign the species to Micralestes on the basis of fin-ray counts, scale counts, and proportional measurements consistent with the genus — details that distinguish it from sympatric or near-sympatric congeners in the lower Congo gorge.
Beyond the characters given in the original description, published information on external coloration, fin detail, and soft morphology of living specimens is limited. As with many newly described alestids from remote fast-water habitats, the available literature is primarily taxonomic rather than ecological or photographic, and detailed colour notes from live fish in the field remain sparse in the accessible record.
Habitat
The type locality of Micralestes schelly is in the vicinity of Inga, Bas-Congo Province (now Kongo Central), Democratic Republic of Congo — a site within the lower Congo rapids corridor, one of the world's most powerful river systems. FishBase records the species as occurring over sand and gravel substrate among large rock slabs in pools up to approximately 7 ft deep, in a freshwater, pelagic, tropical setting. The habitat is characterised by extremely high water velocities in the main channel interspersed with calmer inter-rock pools where smaller fish can shelter and forage.
The lower Congo rapids constitute a biogeographic island of sorts: the gorge from Pool Malebo (Stanley Pool) to Matadi spans roughly 217 mi and drops several hundred metres in elevation, creating hydraulic conditions that have isolated fish populations and driven extensive speciation. Six Micralestes species occupy this corridor, each associated with particular microhabitat and depth conditions within the rapids system. Precise water-chemistry data for M. schelly's exact collecting localities are not available in the accessible literature, but the lower Congo is generally a large, well-oxygenated, soft-to-moderately-mineralised river at this point; temperatures in the lower Congo basin are typically tropical, in the range of the mid-20s Celsius.
Feeding
No specific dietary studies of Micralestes schelly appear in the accessible literature. By analogy with other Micralestes and small alestids from comparable habitats, the species is likely a mid-water forager taking small invertebrates — aquatic insect larvae, small crustaceans, and zooplankton — as its primary prey, with surface-fallen terrestrial insects also taken opportunistically. FishBase categorises the species as a freshwater pelagic fish, consistent with feeding in the open water column between rock features rather than at the substrate.
The high-energy environment of the lower Congo rapids may favour fishes that exploit drift — invertebrates and organic particles swept off rocks or out of substrate by the current — as a significant food pathway. The small body size of M. schelly (under 2 in SL) is consistent with a diet of correspondingly small prey items.
Mating
No published studies of the reproductive behaviour of Micralestes schelly are available. Within Alestidae broadly, small schooling species characteristically spawn in open water or among fine-leaved vegetation, with males competing for access to females through display rather than territory defence. Given the turbulent, structurally complex habitat of the lower Congo rapids, spawning microhabitats likely occur in the calmer inter-rock pools and along the margins of slower side channels, where eggs and fry could persist without being swept downstream.
Alestid fishes generally exhibit external fertilisation with eggs scattered into the water column or deposited loosely among substrate; parental investment is typically absent or negligible. Whether M. schelly shows any departure from this pattern — such as adhesive egg deposition tied to specific rock surfaces — is unknown. The seasonal timing of reproduction in the lower Congo is also undocumented for this species.
Breeding
Captive breeding of Micralestes schelly has not been documented in the accessible hobby or scientific literature. The species is not in established aquarium trade, and its remote, restricted range means that live specimens have rarely if ever been maintained outside of scientific collections. Breeding biology therefore remains inferred from the family pattern: egg-scattering with no parental care, adhesive or semi-adhesive eggs deposited among fine substrate or vegetation, and free-swimming fry requiring small live foods in the early days.
Should the species ever reach specialist fishrooms, approaches proven with other small African tetras — a separate breeding tank, fine-leaved plants or synthetic mops, removal of adults after spawning, and rearing fry on infusoria graduating to newly hatched brine shrimp — would represent the logical starting protocol.
In the aquarium
Micralestes schelly is not currently available in the ornamental fish trade. Its restricted range in the lower Congo rapids, combined with the logistical difficulty and legal complexity of collecting in that region of the Democratic Republic of Congo, means that aquarists have essentially no access to this species. No husbandry literature for it exists in the accessible hobby record.
Were it to become available, the species' small size (under 2 in SL), schooling nature, and mid-water habitat suggest it would behave similarly to other small alestids: a peaceful, active fish suited to a well-oxygenated community aquarium with soft to moderately mineralised water. The lower Congo's naturally high dissolved-oxygen environment implies the species may have a higher oxygen requirement than many tetras, and good surface agitation would be advisable. Until captive stock is established, M. schelly remains a species of scientific rather than hobbyist interest.
Conservation
Micralestes schelly is listed as Data Deficient (DD) on the IUCN Red List, assessed on 16 February 2009. The Data Deficient listing reflects the absence of sufficient population and distribution data to assign a threat category, not a determination that the species is secure. Given its known restriction to a single stretch of the lower Congo rapids — a range measured in tens rather than hundreds of kilometres — the species has inherently limited resilience to any habitat-level disruption.
The lower Congo is one of the world's major proposed hydropower sites. The Grand Inga Dam project, if constructed at or near Inga, would fundamentally alter the hydraulic regime of the type locality and the surrounding rapids that constitute the entire known range of M. schelly and its lower-Congo Micralestes congeners. Large-scale impoundment in this reach would almost certainly constitute an existential threat to a species dependent on the specific fast-water, rocky-pool microhabitat of the free-flowing gorge. FishBase records a high population resilience with an estimated doubling time under 15 months, but resilience models of this kind assume stable habitat, which in the context of a major dam project would not be guaranteed.
Survey work to establish the actual range, population size, and ecological tolerances of M. schelly would be a prerequisite for any meaningful reassessment, and the lower Congo rapids fauna as a whole represents one of the highest-priority gaps in African freshwater fish conservation.