Taxonomy & naming
Rhexipanchax schiotzi was described by J. J. Scheel in 1968, with the species epithet honouring Arne Schiøtz (b. 1932), the Danish herpetologist and aquarist who served as Director of the Danish Aquarium from 1964 and whose fieldwork in West Africa contributed materially to knowledge of the region's fauna. The authority is accordingly presented in parentheses, indicating the name has been placed in a genus other than the one Scheel originally used. The species was originally placed within an expansive circumscription of Procatopus, and Rhexipanchax belongs to the subgenus of Procatopus sensu lato that groups species sharing a distinctively deep-bodied form, grey lateral reticulation, and red body and fin ornamentation in males.
The valid generic placement as Rhexipanchax follows the modern revision of West African lampeye killifish. Eschmeyer's Catalog of Fishes is the governing authority for the current combination Rhexipanchax schiotzi (Scheel, 1968). The genus Rhexipanchax is part of the family Poeciliidae (sensu lato, the lampeyes formerly placed in Aplocheilichthyidae) and is grouped with the African lampeyes — a diverse assemblage of small, schooling killifish found in streams, swamps, and coastal drainages from West to East Africa.
Morphology
Rhexipanchax schiotzi is a small, laterally compressed killifish reaching a maximum recorded total length of 1.5 in, with both sexes attaining similar maximum size. The body is relatively deep for the genus — a trait shared with related Procatopus-group lampeyes — and the flanks show the grey reticulation characteristic of the group, with a net-like pattern of darker pigment over a lighter ground.
Males are the more ornate sex, displaying red markings on the body and fins that intensify during social interactions and courtship. The iridescent light-organ patch above the eye — the feature that gives lampeyes their common name — reflects blue-green in good light and is more conspicuous in males. Females are fuller-bodied when gravid and generally less intensely coloured, with the reticulated flank pattern present but the red ornamentation reduced or absent. The fins are rounded, the dorsal set well back toward the caudal peduncle in the typical lampeye arrangement.
Habitat
Schiøtz's lampeye occupies small permanent watercourses and associated swamps in the forested-savannah transition zone of coastal West Africa. FishBase records its distribution across the lower Volta, Dayi, and Ofu rivers in Ghana; the Sassandra, Comoé, Bandama, and Cavally river systems of Côte d'Ivoire; and the St. John's and Douobe rivers of Liberia, with an unconfirmed record from the Volta in Burkina Faso. Habitat descriptions place it in small rivers, brooks, and swamps within primary forest and forested savannah — waterbodies typically less than 33 ft wide and less than 3 ft deep during the dry season.
These are permanent, non-seasonal waters with stable flow throughout the year, distinguishing the species' ecology sharply from that of annual killifish that inhabit temporary pools. Water chemistry parameters recorded by FishBase include a temperature range of 75–82 °F and a pH of 6.5–7.2, consistent with the moderately soft, near-neutral to slightly acidic conditions typical of West African forested-savannah drainages. The species is described as benthopelagic — occupying the lower to mid water column in association with submerged vegetation, roots, and leaf litter that provide spawning sites and cover.
Feeding
Like other lampeye killifish of the Procatopus group, Rhexipanchax schiotzi is a micro-predator feeding on small invertebrates in the water column and at the surface. The natural diet is presumed to consist of insect larvae, small crustaceans, worms, and other invertebrates of appropriate size for a 1.5 in fish, consistent with the feeding ecology documented for related lampeye species in comparable West African stream habitats.
In aquarium conditions the species accepts suitably sized live and frozen invertebrate foods — daphnia, artemia nauplii, bloodworm, and similar items. Its small mouth limits particle size; foods must be appropriately fine. The schooling habit means competition at feeding time is manageable as long as food is distributed across the water column and not introduced at a single point.
Mating
Rhexipanchax schiotzi is a non-annual, continuous-spawning lampeye. Unlike the annual killies of temporary pools that synchronise reproduction to a short wet season and deposit diapausing eggs in peat or mud, this species inhabits permanent water and spawns intermittently throughout the year, depositing small numbers of eggs at a time. The mating system follows the pattern typical of the Procatopus group: males display to females using the intensified red body markings and the iridescent eye patch, positioning themselves alongside or below a female to display in good light.
Spawning is a pair event in which eggs are deposited individually or in small batches among fine-leaved plants, mosses, roots, and other submerged vegetation where they adhere by a sticky outer coat. There is no bubble-nest construction and no parental guarding; the adults do not tend the eggs after spawning. The continuous-spawning strategy produces a population with overlapping generations and individuals of different ages present simultaneously, as documented for the related Procatopus group by Huber (1999).
Breeding
Eggs are adhesive and attach to fine vegetation or submerged roots where they are deposited. Incubation at the species' preferred temperature range of 75–82 °F takes approximately two weeks, a period reported for the broader Procatopus group by Huber (1999). The relatively extended incubation period compared with annual species reflects the stable, permanent water environment — there is no selective pressure for rapid development in advance of pool desiccation.
Larvae hatch at a small size and begin feeding on micro-organisms and fine particulate matter shortly after becoming free-swimming. In aquarium breeding, the eggs are typically removed from the spawning tank on the plant clumps or mops to which they have been attached, then incubated separately in shallow water with a small amount of antifungal treatment to reduce losses to fungus. Because spawning is continuous, a productive pair will yield a steady trickle of fry over weeks or months rather than a large single clutch. The schooling nature of the species means that adults and fry of different sizes can sometimes be maintained together if adequate vegetation is provided, though dedicated rearing of fry in a separate container improves survival.
In the aquarium
Rhexipanchax schiotzi is a specialist's fish — infrequently encountered in the trade but valued by killifish enthusiasts for the males' subtle but attractive red-and-reticulate patterning and the iridescent lampeye flash. Its small size (1.5 in) makes it suitable for a modest aquarium of 10–15 US gal or larger, provided the tank is densely planted and well-covered — killifish are capable jumpers and gaps in a lid lead to losses. The species does best in soft to moderately hard, near-neutral water reflecting its native stream conditions (pH 6.5–7.2, temperature 75–82 °F).
As a schooling species it should be kept in groups of six or more, with a ratio of more females than males to reduce the attentional load on any individual female. Tankmates, if kept, should be small, peaceful, and of similar size; the fish is not aggressive but can be outcompeted easily by boisterous or large companions. Dense planting with fine-leaved species (Java moss, Ceratophyllum, spawning mops) serves both as refuge and as spawning substrate. Water quality should be stable and clean; regular partial water changes maintain the moderately soft, well-oxygenated conditions the species requires.
Conservation
The IUCN Red List assessed Rhexipanchax schiotzi as Least Concern in November 2019, reflecting its relatively broad distribution across multiple river systems in Ghana, Côte d'Ivoire, and Liberia. The species is not a single-locality endemic and is presumably present in a range of permanent stream and swamp habitats across its West African coastal range, which supports the LC assessment.
Nonetheless, the forests and forested savannahs of coastal West Africa are among the most heavily pressured ecosystems on the continent. Deforestation for agriculture and logging reduces canopy cover and alters stream hydrology, raising temperatures and reducing the complexity of instream habitat. The Cavally and Comoé basins in Côte d'Ivoire and Liberia have experienced substantial deforestation pressure; drainage modification for agriculture and urban expansion affects smaller watercourses disproportionately. The introduction of non-native species — including mosquitofish (Gambusia affinis) and Nile tilapia — into West African streams poses an ongoing threat to small native killies through predation and competition. The species' dependence on permanent, clear, well-oxygenated streams means that any deterioration of water quality or baseflow is likely to affect local populations, even where the regional distribution remains broad.