Taxonomy & naming
Neolebias unifasciatus was described by the Austrian ichthyologist Franz Steindachner in 1894. It belongs to the family Distichodontidae, the African characins, which also contains the much larger and more aggressively plant-grazing Distichodus and the deep-bodied, algae-scraping citharinids — a reminder that within this family adult size and temperament swing enormously between genera, and that Neolebias sits at the small, peaceable end of that range.
The genus Neolebias currently comprises a handful of small West and Central African species, several of which are similar in shape and easily confused without close comparison of the fin and body markings. The species epithet unifasciatus is straightforward Latin for "one-banded", referring to the single dark vertical bar behind the operculum that is the fish's most reliable field mark; some older aquarium literature has treated it under variant spellings or lumped it with related Neolebias forms, so the Catalog of Fishes (Eschmeyer, California Academy of Sciences) remains the reference point for the currently accepted name.
Morphology
This is a genuinely small fish: FishBase gives a maximum published length of 1.5 in standard length (about 2 in total length), placing it among the smallest characins kept in the hobby. The body is slender and laterally compressed, with a small, terminal mouth set with tiny teeth suited to picking at small food items rather than biting.
The defining mark is the single dark vertical band running down the flank just behind the gill cover, which gives the species both its scientific and common names. Base colouration is a subdued silvery-olive to tan, without the bright reds or oranges seen in some other small African characins, and the fins are typically clear to lightly dusky. It is an unshowy fish whose appeal lies in its schooling behaviour rather than individual colour.
Habitat
Neolebias unifasciatus has a broad Central and West African range, recorded from the Gambia basin east through the Chad basin (though apparently absent from the Senegal River itself) and across the Congo basin, with records also from Cameroon and Gabon south to the Chiloango system in the Democratic Republic of the Congo. Across this range it occupies small lowland streams, swampy margins and still or slow-flowing backwaters, typically among dense vegetation and submerged branches rather than in open water.
Water conditions are tropical and on the soft, mildly acidic side: FishBase reports a temperature range of roughly 75–82 °F and pH 6.0–7.0 for the species. This is warm West and Central African river and swamp water rather than the harder, cooler conditions found in some other parts of the continent, and it is often at least lightly tannin-influenced given the vegetated, shaded habitats the species favours.
Feeding
Neolebias unifasciatus is an omnivorous micropredator. FishBase's trophic-level estimate (3.5) places it as a secondary consumer, and aquarium sources describe a small mouth and tiny teeth suited to picking small crustaceans and other invertebrates from the water column and off plant surfaces rather than grazing algae or plant matter, unlike its larger Distichodus relatives.
In the wild this likely means small zooplankton, aquatic insect larvae and other tiny invertebrates. In the aquarium, keepers report the species does well on small live and frozen foods — micro-worms, baby brine shrimp, Daphnia and similarly sized fare — alongside high-quality micro-pellet or flake foods once acclimated; its small mouth means food size matters more than variety.
Mating
Detailed courtship behaviour for Neolebias unifasciatus is not well documented in the available literature. What is recorded is the species' general shoaling, timid temperament: it is described as an active, schooling fish that keeps to cover and is most settled in a group of eight or more, which is also the social context in which spawning is most likely to be observed. Specific external sexual dimorphism is not established in the sources available here; data sparse.
Breeding
As with many small Distichodontidae, Neolebias unifasciatus is presumed to be an egg-scattering species typical of the family, but it is not a fish that is regularly or reliably bred in the home aquarium, and detailed accounts of successful captive spawning are scarce in the sources available here. Where small Neolebias species have been bred, reports generally describe adults scattering fine, non-adhesive eggs among fine-leaved plants or spawning mops with no parental care, and the parents will readily eat their own eggs and fry if left in the tank — but this species-specific breeding is not well documented, and prospective breeders should treat it as a project with limited published guidance rather than a routine spawn.
In the aquarium
Neolebias unifasciatus is a shy, small nano fish that needs to be kept as a proper shoal — aquarium sources recommend eight or more individuals — in a heavily planted tank with branches or other cover to retreat into; kept singly or in a bare tank it is described as nervous and prone to hiding. Given its adult size of barely 2 in, a modest aquarium is entirely adequate, but tankmates should be equally small and peaceable, since this is not a fish that can compete with boisterous or much larger species for food.
Water should be kept warm (roughly 75–82 °F) and on the soft, mildly acidic side (pH 6.0–7.0), consistent with its Central and West African stream and swamp habitats. It is reported to be active through both day and night, tending to settle and hide after dark, so subdued lighting and floating cover are appreciated. It remains rare in the aquarium trade, so availability is inconsistent and a keeper who finds it should expect a genuinely uncommon fish rather than a routine store staple.
Conservation
The IUCN Red List assesses Neolebias unifasciatus as Least Concern, reflecting its wide distribution across multiple West and Central African river basins from the Gambia to the Congo and the absence of any documented major population decline. It is not a species of particular conservation concern at present.
As with many small, widely distributed African stream fish, there is limited targeted monitoring of this species specifically, so its conservation status rests more on its broad range and habitat tolerance than on detailed population data. General pressures on Central and West African freshwater habitats — deforestation, wetland drainage and water-quality degradation — are relevant long-term considerations for the species' habitat even though it is not currently listed as threatened.