Taxonomy & naming
Plataplochilus pulcher was described by Lambert in 1953, with the type locality given as Gabon. The genus Plataplochilus is placed within the family Procatopodidae (or the procatopodine lampeyes of Nothobranchiidae, depending on the classification followed), a group of small, non-annual egg-laying killifish endemic to western and central Africa. Eschmeyer's Catalog of Fishes treats Lambert, 1953 as the valid authority for this species.
A locality variant catalogued under the designation 'miltotaenia' has been documented by the American Killifish Association as associated with populations of P. pulcher; the relationship between miltotaenia and the nominate form remains under discussion in the hobby literature, with some sources treating it as a synonym and others as a distinct population variant. The closely related Plataplochilus chalcopyrus occurs in western Gabon in the Mouila region, and Plataplochilus eliasi was described from the Mayumbe mountains of the wider Congo basin. This tight group of Gabon-centred lampeyes is among the least-studied procatopodines in terms of formal ichthyological revision.
Morphology
Plataplochilus pulcher is a slender, laterally compressed lampeye reaching approximately 1.5 in standard length. As in all lampeyes, the most striking feature is the iridescent supra-orbital light organ — a patch of specialised photophore-like tissue just above the eye that reflects blue-green metallic light and is thought to function in intraspecific communication and schooling coordination in shaded forest waters.
The body is elongate and torpedo-shaped, typical of schooling procatopodines. The closely related sister species P. miltotaenia is described in the hobby literature as displaying an electric-blue iridescent body with yellow highlights on the fins — characters that are likely shared with or approach those of P. pulcher given the two taxa's proximity. The dorsal and anal fins are positioned well back on the body, meeting near the caudal peduncle in the manner characteristic of killifish. Sexual dimorphism is present: males are more intensely coloured, with brighter iridescence, while females are plainer and rounder when carrying eggs.
Habitat
Plataplochilus pulcher inhabits permanent freshwater — small streams, forest brooks, and swamp margins — in Gabon, west-central Africa. Its documented collection locality at Lambaréné sits on the Ogooué River system, which drains a large portion of Gabon through equatorial lowland forest and gallery woodland. These are permanent, non-seasonal waters, in contrast to the temporary seasonal pools used by annual killifish; Plataplochilus species are characteristic of the stable, shaded, slow-to-moderate streams and swamp edges of the western Congo basin region.
Water in these habitats tends to be soft to moderately mineralised, well-oxygenated, and lightly stained by leaf tannins — conditions typical of west-central African forest stream communities. Related species in the genus occupy similarly quiet, shaded, permanent environments in western Gabon and the adjacent Congo basin, suggesting a consistent ecological preference across Plataplochilus as a whole.
Feeding
In nature, Plataplochilus pulcher feeds on small invertebrates at or near the water surface — a feeding strategy common to procatopodine lampeyes, whose upturned mouths and position in the water column reflect a specialisation for picking micro-crustaceans, insect larvae, and emerging insects from the film. The diet in forest stream habitats likely includes chironomid larvae, copepods, cladocerans, and other small zooplankton.
In the aquarium the species accepts a wide range of small live and frozen foods: Daphnia, Cyclops, Artemia nauplii, micro-worms, and small chironomid larvae (bloodworm) are all taken readily. Finely ground flake or micro-pellet foods are accepted but live and frozen foods are strongly preferred and support the best colour development. Feeding twice daily in small portions suits its continuous active metabolism.
Mating
Plataplochilus pulcher is a non-annual continuous spawner — it breeds in small batches over an extended period rather than in a single seasonal burst. This reproductive strategy is characteristic of procatopodine lampeyes that inhabit permanent water, where there is no dry-season cue to trigger mass spawning and no need for diapausing eggs capable of surviving habitat desiccation.
Males display to females with spread fins and intensified iridescence, typically courting in open water or near fine-leaved vegetation. The spawning act is brief: male and female come alongside each other and a single adhesive egg is extruded and fertilised. Eggs in the genus Plataplochilus carry a short adhesive filament (0.5 in) that anchors them to plant surfaces, roots, or fine substrate debris, preventing them from drifting into unfavourable conditions. Males may court multiple females over the course of a day, and females deposit a few eggs at a time rather than a large clutch in a single event.
Breeding
Under aquarium conditions, Plataplochilus pulcher spawns continuously when maintained in clean, well-oxygenated water at appropriate temperatures. The adhesive eggs, secured by their filament to fine-leaved plants such as Java moss, floating roots, or spawning mops, require no special incubation conditions beyond a stable temperature and the absence of fungal infection; a light antifungal treatment (acriflavine or methylene blue) helps in bare breeding setups.
Eggs hatch in approximately 10–14 days depending on temperature. The fry are small but free-swimming immediately at hatching and require appropriately sized first foods: infusoria, vinegar eels, or commercial micro-fry food for the first week, graduating to freshly hatched Artemia nauplii and micro-worms as they grow. Because adults in a community setting may consume eggs and small fry, dedicated breeding pairs or a dense plant cover improves yield. Continuous collection of eggs from a spawning mop every few days and transfer to a hatching container is the standard approach used by specialist killifish keepers.
In the aquarium
Plataplochilus pulcher is a specialist's fish — not commonly encountered in the trade outside of killifish society networks, but a rewarding species for aquarists with an interest in west African lampeyes. It is best kept as a small school of six or more individuals in a softly lit, well-planted tank of 10–15 US gal, with floating plants and fine-leaved vegetation providing the shaded, dappled conditions it prefers in nature. A dark substrate and tannin-stained water (from dried leaves or peat filtration) enhance colour and reduce stress.
Water conditions should reflect its Gabonese forest stream origin: soft to moderately hard (general hardness 2–10 °dH), slightly acidic to neutral (pH 6.0–7.2), and warm (72–79 °F). Excellent filtration maintaining high oxygen levels is important; a gentle surface flow suits the species well. Compatible tankmates are limited to similarly sized, non-aggressive fish that will not outcompete it at feeding — other small west African killifish, small tetras, or dwarf rasboras in a biotope setup. Mixing with boisterous or nippy species is not recommended.
Conservation
Plataplochilus pulcher has not been formally assessed by the IUCN Red List and currently holds a status of Not Evaluated (NE). This absence of assessment is common among the less commercially prominent west African killifish — even species with restricted distributions may never receive formal scrutiny if they lack a hobbyist profile sufficient to bring them to assessors' attention.
The species is endemic to Gabon, with its known range centred on the Ogooué basin around Lambaréné. Like many small stream killifish of equatorial Africa, it faces diffuse but real pressures from deforestation and agricultural encroachment on lowland forest streams, watershed modification, and the general degradation of small watercourse habitats across the region. The introduction of mosquitofish (Gambusia species) as a vector-control measure in parts of Africa is an additional threat to small surface-dwelling lampeyes wherever the two co-occur. Given its small body size, permanent-water habitat, and restricted Gabonese range, formal assessment and systematic field surveys would be warranted to establish whether wild populations are secure.