Taxonomy & naming
Scriptaphyosemion brueningi was described by the German aquarist and ichthyologist Eberhard Roloff in 1971. The authority is given in parentheses because the name combination has since been reworked: Roloff's original genus assignment has changed and the current valid combination places the species in Scriptaphyosemion, a genus erected to accommodate a clade of non-annual West African killies within the family Nothobranchiidae. Eschmeyer's Catalog of Fishes (CAS) is the governing authority for the valid name, and FishBase lists the species under the combination Scriptaphyosemion brueningi (Roloff, 1971).
The genus name Scriptaphyosemion refers to its placement within the broader aphyosemion-grade killifish, prefixed by the Latin scripta, meaning 'marked' or 'inscribed', alluding to the complex patterning characteristic of members of the group. The specific epithet brueningi honours Christian Brüning (died 1943), a German aquarist who contributed to the early study and popularisation of West African killies in the European hobby. This eponymous naming tradition is widespread in killifish taxonomy.
Morphology
Scriptaphyosemion brueningi is a slender, laterally compressed killifish reaching a maximum total length of approximately 2.5 in, with most adults around 2 in TL. Like other members of the genus, males display vivid, intricate colouration — typically a mosaic of red, blue, and orange marks on the flanks, with patterned, coloured unpaired fins that play a key role in male-to-male signalling and courtship. The caudal fin often carries prominent pigment extensions or lyrate lobes.
Females are considerably more cryptic: smaller, rounder in the belly, and brownish to olive in base colour with minimal fin ornamentation. Sexual dimorphism is thus pronounced and diagnostic — a characteristic of virtually all Scriptaphyosemion species, and one that simplifies sexing in the aquarium. The body profile is streamlined and adapted to life in slow-moving or still forest water, where the fish moves through dense vegetation near the surface and substrate.
Habitat
In the wild, Scriptaphyosemion brueningi occupies swamps and the swampy margins of small brooks and forest streams in the Bomi Hills area of Sierra Leone and adjacent Liberia. These are non-seasonal, permanent or near-permanent water bodies set within lowland rainforest and forested savanna mosaic — a critical distinction from the seasonal, clay-pool habitats of annual killifish. The waters are typically shallow, heavily shaded by overhanging vegetation, and tea-coloured with dissolved tannins and humic acids leached from leaf litter and decaying wood.
FishBase records a water chemistry envelope of approximately pH 5.8–7.2, indicating tolerably soft to slightly acid conditions — broadly typical of West African lowland forest streams. Water temperatures in the region are relatively stable year-round in the lower to mid-twenties Celsius, without the extreme seasonal drying and flooding that drives the annual-killi life cycle further inland and in savanna zones. The species shares this humid-forest niche with other Scriptaphyosemion and related non-annual aphyosemion-grade killies.
Feeding
Like most killifish, Scriptaphyosemion brueningi is a microcarnivore in the wild, hunting small invertebrates — aquatic insect larvae, worms, microcrustaceans, and similar prey — among the surface film and dense vegetation of its forest-stream habitat. FishBase records a trophic level of 3.2 (± 0.5 s.e.), confirming a mid-level predatory position consistent with an insectivore-dominated diet.
In captivity the species readily accepts a range of small live and frozen foods: Daphnia, Artemia nauplii, bloodworm, Cyclops, and tubifex. Small-gape prepared foods formulated for killifish are also taken. Feeding frequency should be moderate and portion sizes small — these are compact fish in a modest-volume tank, and overfeeding degrades water quality quickly. Variety in the diet, especially regular live or frozen invertebrates, promotes the best colouration in males.
Mating
Scriptaphyosemion brueningi is a non-annual plant-spawner. Pairs court among fine-leaved plants or floating vegetation near the surface, with the male displaying his vivid colouration and extended fins to the female in a ritualized courtship that can involve extended chasing, parallel swimming, and lateral displays. There is no bubble-nest building and no soil-burying of eggs; instead the pair spawn in brief embraces among vegetation or into a spawning mop, depositing a small number of adhesive eggs at each pairing.
Because the species inhabits permanent water bodies, it lacks the pressure to compress its entire reproductive effort into a single brief wet-season pulse as annual killies must. Pairs in stable aquarium conditions can spawn repeatedly over days and weeks, continuously depositing small clutches. The male's colouration intensifies in the presence of a receptive female and serves as an honest signal of condition in the dense, shaded habitat where visibility is limited.
Breeding
Eggs are small, adhesive, and deposited singly or in small batches on fine-leaved plants, Java moss, or artificial spawning mops positioned near the water surface or resting on the substrate. They are incubated in water — not in moist peat or soil — and do not require a diapause period, which is the hallmark of the non-annual breeding mode. Incubation takes approximately two to three weeks at aquarium temperatures in the low-to-mid twenties Celsius; the hobbyist literature recommends picking eggs into a small container of tank water with a little methylene blue to prevent fungal losses.
Fry hatch as miniature replicas of the adults and are immediately free-swimming. First foods are infusoria or commercial fry powder; within a week most fry can take freshly hatched Artemia nauplii. Growth is reasonably steady and fish typically reach sexual maturity within a few months. Because adults will eat eggs and small fry, the spawning substrate or the pair themselves should be removed promptly once eggs are found. Water quality must be maintained carefully during the fry rearing phase, as small containers used for egg hatching are prone to fouling.
In the aquarium
Scriptaphyosemion brueningi is described as difficult to maintain in captivity by FishBase — a rating that reflects the specific water-quality demands of a soft-water forest species, rather than aggression or extreme dietary fussiness. The aquarium should be small (10–15 US gal is ample for a pair or trio), heavily planted or provided with spawning mops, and kept dimly lit to replicate the shaded forest environment. Soft, slightly acid water (pH 5.8–6.8, very low hardness) and scrupulous maintenance are essential; the species does not tolerate the elevated nitrate levels and hardness that many community fish accept without issue.
A tight-fitting lid is mandatory — killifish are exceptional jumpers. Males will spar and display to one another, so a single male with one or two females is the typical approach; aggression in a small tank can stress or wound a subordinate male. The species is best maintained as a species tank or with very small, peaceful dither fish of similar water-chemistry requirements. It is primarily an aquarium-hobbyist species rather than a widely traded commercial fish, and sourcing typically goes through specialist killifish societies and breeders. The recorded strain Peie SL89 traces to a collection locality at Peie in Sierra Leone.
Because of its Vulnerable status and restricted wild range, captive populations held by killifish enthusiasts carry genuine conservation value. Maintaining clean genetic lineages linked to known collection localities, as the killifish hobby's tradition of strain-code labelling enables, contributes meaningfully to ex-situ preservation.
Conservation
The IUCN Red List assessment of 2020 places Scriptaphyosemion brueningi in the Vulnerable (VU) category under criterion B1ab(iii), assessed by H. Dankwa. The criterion indicates that the species' extent of occurrence is estimated as restricted (less than 20,0 mi²), that the range is severely fragmented or exists at few locations, and that there is a continuing decline in the extent and quality of habitat. The full assessment is available at https://www.iucnredlist.org/species/181886/134762655.
The primary threat is the ongoing loss and degradation of lowland rainforest and associated freshwater habitats in Sierra Leone and Liberia — a region that has experienced some of West Africa's most intensive deforestation through logging, agricultural conversion, diamond and iron-ore mining, and the displacement of rural communities. The Bomi Hills area, the core of the species' known range, has been substantially altered by industrial mining operations. Swamp drainage for agriculture further reduces available habitat.
As a species reliant on permanent swamp and forest-stream microhabitats within a small geographic range, Scriptaphyosemion brueningi is acutely sensitive to any reduction in the extent or hydrological integrity of those systems. Captive populations maintained by killifish hobbyists, carefully labelled by collection strain (notably Peie SL89), represent a potentially important safeguard, but the species is not the subject of any coordinated ex-situ conservation programme. Protection of remaining lowland forest and associated freshwater habitats in the Bomi Hills region is the most critical factor for the long-term survival of this species in the wild.