Taxonomy & naming
Aapticheilichthys websteri was described in 2007 by the French killifish specialist Joerg Huber in the Tropical Fish Hobbyist Magazine, based on material collected at Akaka Camp, a lodge site on the western coastal plain of Gabon at approximately 2°14′S, 9°40′E. The original combination was Procatopus websteri Huber, 2007; the authority is presented in parentheses to indicate the species has since been transferred to a new genus. Huber subsequently erected the monotypic genus Aapticheilichthys to accommodate the species, recognising that it differed from all other lampeye genera in a single but unambiguous morphological feature: the dorsal and anal fin insertions are superimposed (directly above one another) rather than the anal fin insertion sitting anterior to the dorsal, as is universal elsewhere in the lamprichthyine assemblage.
The family placement has shifted with modern phylogenetics. Traditional treatments placed lampeyes in the family Procatopodidae or Aplocheilichthyidae; current classification, as recognised by GBIF and the broader literature, nests them within Poeciliidae, reflecting molecular evidence for the grouping. Eschmeyer's Catalog of Fishes is the authority for the valid name Aapticheilichthys websteri (Huber, 2007).
The species epithet websteri honours a collector or patron named Webster; the cache does not record the identity of the dedicatee beyond the surname. The genus name Aapticheilichthys is formed from Greek roots connoting the fish's lampeye affinity, differentiating it within that clade.
Morphology
Aapticheilichthys websteri is a small, deep-bodied fish. The holotype measured 1 in standard length (SL), and paratypes ranged from 0.5–1 in SL, placing it among the smaller members of the lamprichthyine assemblage. The body profile is notably deep for its length, and the mouth is pointed — a typical lampeye feature suited for sipping small surface or mid-water invertebrates.
Colouration in males is striking for so small a fish. An orange iridescent spot sits above the eye margin — the characteristic 'lamp' of the group, formed by a specialised light-organ patch of reflective pigment. The flanks show a grey reticulation, and the unpaired fins (dorsal, anal, and caudal) carry red curved bars that contrast with the background. Females are plainer, lacking the intense fin markings. The superimposed dorsal and anal fin insertions — the primary diagnostic character of the genus — are visible externally: when the fish is viewed from the side, the origins of both fins sit at the same point along the dorso-ventral axis of the body, unlike any other lampeye.
Habitat
The only confirmed locality for Aapticheilichthys websteri is the river frontage at Akaka Camp, western coastal plain of Gabon (approximately 2°14′S, 9°40′E), at or near sea level. The Tropical Fish Hobbyist description records a freshwater river less than 33 ft wide and less than 3 ft deep at the collection site, with warm, slightly acidic water. FishBase records the temperature as exceeding 80 °F and the pH as just over 6 — clear, warm, gently flowing water typical of lowland coastal-plain forest streams in equatorial West Africa.
The habitat is permanent (non-seasonal) flowing water, consistent with the non-annual reproductive strategy of the species. Schooling behaviour in small mixed-age groups, as noted in FishBase, suggests the fish inhabits areas of moderate cover — submerged roots, marginal vegetation, or leaf litter banks — that provide refuge from current and protection for the tiny fry.
Feeding
Aapticheilichthys websteri is microphagous, feeding on the small invertebrates typical of lampeyes in permanent forest-stream habitats. The pointed mouth and small gape indicate a diet of aquatic insect larvae, microcrustaceans, and other invertebrates at or near the water surface and in the mid-water column — a feeding strategy shared broadly across the lamprichthyine lampeyes of West and Central Africa.
In aquarium conditions, small live or frozen foods such as artemia nauplii, micro-worms, and daphnia are appropriate. The fish's small mouth limits the particle size it can accept, and prepared foods should be fine-grained. Feeding little and often suits the schooling, active nature of the species.
Mating
As a non-annual lampeye, Aapticheilichthys websteri breeds continuously in permanent water rather than synchronising reproduction with a seasonal dry period as annual killifish do. The mating system is typical of lamprichthyine lampeyes: males display the iridescent orange lamp patch above the eye and the red fin markings to court females, with competition between males likely mediated by these visual signals.
Females select mates and spawning sites among fine-leaved plants or submerged roots at the water's edge. Spawning is protracted — individual pairs or small groups return repeatedly over days and weeks to deposit small numbers of eggs rather than committing all reproductive investment to a single event. This scatter-spawn strategy, delivering adhesive eggs a few at a time to sheltered attachment sites, spreads reproductive risk and produces overlapping cohorts of fry, consistent with the mixed-age schooling noted from the type locality.
Breeding
FishBase records an egg incubation period of approximately two weeks for Aapticheilichthys websteri, consistent with other non-annual West African lampeyes in warm tropical conditions. Eggs are adhesive and attached to fine plants or root mats at the time of laying; no diapause or desiccation tolerance is involved. Larvae hatch fully formed for their size and are free-swimming almost immediately, beginning to feed on infusoria-grade particles within days.
In the aquarium, breeding is best encouraged in a species tank or with very small, non-competitive tankmates. Clumps of fine-leaved plants (java moss, hornwort, or floating plants with trailing roots) provide spawning substrate. Because eggs are scattered individually over an extended period, systematic removal of plant clumps to a separate hatching vessel is a practical method of rearing fry without adult predation. Water temperature above 79 °F and a slightly acidic pH (6.0–6.5) replicate natural conditions and support successful reproduction.
In the aquarium
Aapticheilichthys websteri is a rare fish in the hobby, known from only a single collection locality and unlikely to appear in the trade with any regularity. When encountered — occasionally through specialist killifish societies such as the American Killifish Association — it merits a dedicated species tank that respects its small size and schooling nature. A group of six or more individuals in a 10–15 US gal, well-planted aquarium with a secure lid and gentle filtration provides appropriate conditions.
Water should be warm (81–86 °F), slightly acidic to neutral (pH 6.0–7.0), soft to moderately hard, and well-oxygenated despite the slow current of its native habitat. The orange lamp patch above the eye and the red-barred fins of the male are best appreciated under good lighting against a dark substrate and background planting. The fish are active schoolers and should never be kept singly. Because the species is a continuous spawner in permanent water, a small but steady supply of eggs can be maintained in a healthy colony — making captive propagation through killifish societies the primary means of keeping the fish in culture.
Conservation
Aapticheilichthys websteri has never been formally assessed by the IUCN Red List. Its conservation status is Not Evaluated (NE), a designation that reflects absence of assessment rather than security. The biological facts are sobering: the species is known from a single point locality on the western coastal plain of Gabon, an area of lowland coastal forest under pressure from logging, agricultural expansion, and infrastructure development. A single-locality endemic with no confirmed populations elsewhere has zero buffer against local extinction events.
The coastal plain streams of western Gabon are among the lesser-studied freshwater systems in equatorial Africa; additional survey work might reveal further populations of Aapticheilichthys websteri, but until such surveys are conducted the species must be treated as highly range-restricted. The integrity of the Akaka Camp river and its riparian forest corridor is the proximate conservation concern. A formal IUCN assessment using the B-criterion (extent of occurrence and area of occupancy for narrow-range endemics) would almost certainly result in a threatened category, likely Vulnerable or Endangered at minimum. Maintenance of captive populations through specialist killifish societies provides a modest insurance policy against the loss of the only known wild population.