Taxonomy & naming
Aphyosemion bamilekorum was described by Alfred Radda in 1971 from material collected in the Mifi District of western Cameroon, with the type locality given as the upper Noun River in the Sanaga River system, approximately 6 mi north-west of Bafoussam. The name is treated as valid by Eschmeyer's Catalog of Fishes (Fricke, Eschmeyer & Fong), placing it within the large and species-rich genus Aphyosemion — the most diverse genus of African non-annual killifishes.
A. bamilekorum sits somewhat apart from many of its congeners in body shape. The AKA (Association Killifish Aquaristes) notes that its unpaired fins display a pattern of radiating spots and lines but lack the distinctive contrasting outer margins that characterise most Aphyosemion species, giving the fish a subtly different silhouette. No subspecies are currently recognised. The species is not known to have been the subject of a formal taxonomic revision since its original description, though ongoing field work by Cameroonian and European researchers has clarified aspects of its distribution.
Morphology
Males reach approximately 1.5 in total length; females are slightly smaller at around 1.5 in TL. For an Aphyosemion the body proportions are somewhat atypical: the AKA characterises the form as unusual within the genus, with the dorsal and anal fins carrying radiating spots or linear markings rather than the bold, contrasting outer margins that frame the fins of many relatives. The base colouration follows the genus's general template of an iridescent greenish to bluish body with red to brown spotting, though the highland population's precise colour pattern in life should be verified against photographs of wild-caught or F1 individuals.
Sexual dimorphism is moderate and typical for the genus: males are more intensely coloured with larger, more ornate fins, while females are drabber, brownish or olive, with smaller, rounded fins. The difference becomes apparent by the time the fish are several months old, though the AKA notes that reliable sexing in this species can take up to twelve months given its slow development.
Habitat
Aphyosemion bamilekorum is endemic to a narrow band of the Bamileke plateau in the West Region of Cameroon, centred on the area between Bafoussam and Mbouda at approximately 1,0 ft altitude. The type locality in the Mifi District drains into the upper Noun River, itself part of the Sanaga River system. Field water readings recorded by the AKA from this zone are unusually cold and soft for West Africa: temperatures of 65–69 °F, pH 5.8–6.3, and total hardness of DH 1–3 — water that is close to distilled in its mineral content and distinctly acidic.
The habitat consists of fast-running, shaded highland brooks with overhanging riparian vegetation that helps maintain the cool temperatures and low light. The substrate is likely sand or gravel with accumulated leaf litter in slower-moving margins. This montane specialist is not a seasonal-pool fish — its streams flow year-round (or near year-round) and it is therefore a non-annual species. The Rufford Foundation has funded active field research assessing the distribution and remaining population size of A. bamilekorum, reflecting the perceived urgency of understanding a species whose range may be even more fragmented than originally documented.
Feeding
In the wild, Aphyosemion bamilekorum almost certainly preys on small invertebrates — aquatic insect larvae, microcrustaceans, and terrestrial insects that fall onto the water surface — consistent with the diet of other small Aphyosemion species in forest and highland streams. No specific gut-content studies appear to have been published for this species.
In the aquarium, the AKA reports that the fish is not particularly difficult to feed once settled: live or frozen artemia (brine shrimp), Daphnia, chironomid (bloodworm) larvae, and tubifex are appropriate foods. Small, meaty live or frozen items are most effective in encouraging conditioning for spawning. As with most small Aphyosemion, varied feeding that closely mimics the invertebrate-rich natural diet keeps fish in best condition.
Mating
Aphyosemion bamilekorum is a non-annual killifish. Rather than the soil-burial and diapausing-egg strategy of annual species, it spawns on or near fine-leaved plants, roots, or artificial spawning mops in the manner typical of plant-spawning Aphyosemion: the pair swim close together, the male positioning himself alongside or slightly below the female, and eggs are deposited individually or in small batches in the spawning medium, where they adhere and develop in water without any dry period.
The AKA describes this species as a somewhat reluctant spawner relative to other Aphyosemion — pairs are not frequent egg layers and output per session is low. Males can be mildly aggressive toward females and should be watched; providing a ratio of one male to two females, or using a tank with sufficient cover, reduces harassment. Cool water (65–70 °F), very soft and acidic chemistry (pH 5.8–6.5, DH 1–3), dim lighting, and the presence of peat fibre in the substrate or as a filter medium all contribute to successful spawning.
Breeding
Eggs can be collected from spawning mops or fine-leaved plants and incubated in small containers of soft, slightly acidic water at 64–68 °F. The AKA records incubation times of 14–21 days in water at these temperatures, or approximately one month if eggs are briefly rested on damp peat — an intermediate approach used by some keepers to reduce fungal pressure. There is no obligate dry incubation period: this is not an annual-mode species and eggs kept continuously moist will hatch on a normal schedule without diapause.
Fry are small and slow-growing. They should be started on infusoria or the finest-grade commercial fry foods, then moved to freshly hatched artemia nauplii as soon as they can take them. The AKA notes that growth is particularly gradual and that it may take up to twelve months before juveniles can be reliably sexed. This slow development, combined with the low egg output per spawning, makes building a colony of A. bamilekorum a patient undertaking. Regular small water changes with aged, very soft water are important throughout the grow-out period, as the species is sensitive to dissolved metabolic waste.
In the aquarium
Aphyosemion bamilekorum is considered a difficult species — not in terms of temperament or aggression, but because its requirements depart significantly from typical tropical aquarium conditions. The cool highland temperatures of its native streams (64–72 °F) mean that standard tropical heaters set to 79 °F will cause stress or early mortality; the aquarium must instead be kept in a cool room or actively cooled in summer. In mild climates an unheated tank can work year-round, but a temperature probe and contingency cooling are essential.
Water chemistry must closely match the natural range: very soft (DH 1–3), moderately acidic (pH 5.8–6.5), and clean. Peat filtration, rainwater or reverse-osmosis water, and regular partial changes with chemistry-matched top-up water are the standard approach. A densely planted, low-flow aquarium with subdued lighting and a dark substrate is appropriate. The species should not be mixed with fast-swimming or aggressive tankmates; other cool-water, soft-water species are acceptable if needed, but a species-only tank is safest and most likely to yield spawning. The FishBase entry cautions that the species is difficult to maintain in aquarium conditions, underscoring the need for careful water management.
Conservation
The IUCN Red List assessed Aphyosemion bamilekorum as Endangered (EN) in February 2009 under criteria B1ab(iii)+2ab(iii), which reflect both a small estimated extent of occurrence and area of occupancy and an inferred continuing decline in the quality of its habitat (specifically, the extent and condition of freshwater ecosystems). The 2025-2 Global assessment retains this status. The species is known only from a restricted plateau in the West Region of Cameroon, where its montane brook habitat is under pressure from agricultural expansion, deforestation, and small-scale development on the Bamileke plateau — one of Cameroon's most densely settled highland regions.
The Rufford Foundation funded a dedicated field project led by Eric Joselly Kouedeum Kueppo to document the current distribution, population size, and conservation status of the species in the West Region, indicating that the 2009 assessment data were insufficient and that updated field surveys were warranted. The narrow altitude band the species occupies, its extreme water-chemistry specialisation, and the ongoing transformation of Cameroonian highland stream catchments by farming and cattle-grazing make it one of the more ecologically vulnerable Aphyosemion species. No captive-assurance colony programme is known to have been formally coordinated at the time of writing.