Taxonomy & naming
Petrocephalus schoutedeni was described by the Belgian ichthyologist Max Poll in 1954, in his paper on the forest fishes collected around Yangambi, near Stanleyville, in the Belgian Congo. It is placed in the family Mormyridae — the elephantnoses and mormyrids — within the order Osteoglossiformes, the bonytongue fishes, one of the oldest surviving lineages of teleosts. The type locality is a set of forest streams around Yangambi, on the Congo River in what is now the Democratic Republic of Congo; the holotype, MRAC 120045, is held with an unusually large paratype series of fifty specimens.
Within Petrocephalus, the species is placed in an informal group built around P. microphthalmus, defined by the loss of the rostral knollenorgan rosette that most of the genus carries on the snout. No synonyms are documented in the sources consulted for this account, and the species has not been the subject of a taxonomic revision since its original description.
Morphology
Petrocephalus schoutedeni is a small mormyrid, reported at about 3.5 in; the sources consulted do not specify whether that figure is standard or total length. Like its relatives it has a laterally compressed, moderately deep body, a short blunt head, and a small, underslung mouth set low beneath the snout — a design built for slow, deliberate foraging near the bottom rather than open-water speed.
The species' most distinctive feature is on the head rather than the body: it entirely lacks the electroreceptive rosette organs — the augen, nacken, and kehl organs — that most Petrocephalus species carry as clusters of specialized receptors on the crown, nape, and throat. Only three other species in the genus share this condition: P. microphthalmus, P. haullevillii, and P. zakoni. As in all mormyrids, an electric organ near the base of the tail still generates a weak pulse discharge; genus-wide recordings show Petrocephalus produce short, triphasic pulses that differ between species in amplitude, duration, and dominant frequency, but no discharge has been recorded and published specifically for P. schoutedeni.
Habitat
The type locality is a set of forest streams around Yangambi, in the central Congo basin of the Democratic Republic of Congo, and this remains the one locality tied directly to Poll's original description. Some later compilations extend the species' listed range far to the west, into Upper Guinea coastal drainages — the Sassandra River, the upper Cavally, and the Niandan, a tributary of the Niger — spanning Sierra Leone, Guinea, Côte d'Ivoire, Liberia, and Ghana.
A single species occurring in both the Congo basin and West African coastal rivers, with nothing documented in between, is an unusual distribution, and the sources consulted flag it as needing reconciliation rather than treating it as settled. Until a taxonomic review clarifies the picture, the Congo basin population at Yangambi is the one with a secure identification; water chemistry data — temperature, pH, or substrate — are not documented for the species in either part of its reported range.
Feeding
Diet has not been documented for Petrocephalus schoutedeni specifically. Mormyrids as a group forage on small benthic invertebrates — insect larvae, worms, and tiny crustaceans — located by electrolocation in mud, silt, and leaf litter, but this pattern has not been confirmed by direct study of this species.
Mating
Courtship and mating behavior have not been described for this species. In mormyrids generally, the electric organ discharge is thought to carry information relevant to courtship and to species and sex recognition, alongside its role in navigation and prey detection, but this remains a genus-level inference rather than an observation made in Petrocephalus schoutedeni.
Breeding
Breeding is unrecorded for Petrocephalus schoutedeni — no wild or captive spawning account has been published. As with most Petrocephalus and Mormyridae generally, reproduction in the wild is presumed to track seasonal rains and rising river levels, but that is an extrapolation from the family rather than a documented fact for this species.
In the aquarium
Petrocephalus schoutedeni has essentially no track record in the aquarium hobby; it does not appear to be an established import, and the sources consulted contain no husbandry accounts specific to it. Any fishkeeping notes here describe general practice for small Petrocephalus mormyrids rather than experience with this species.
Where a small mormyrid of this kind is kept, the usual approach is a soft sand substrate for probing, dim lighting, and ample cover such as roots or leaf litter, in stable, clean water with low turbidity — mormyrids as a family are known to be sensitive to poor water quality and to common aquarium medications, so cautious dosing and gradual acclimation matter more than with most community fish. Live or frozen invertebrate foods offered after dark suit the natural foraging rhythm of the genus better than daytime flake feeding.
Conservation
The IUCN Red List classifies Petrocephalus schoutedeni as Least Concern, based on a 2020 assessment. The assessment does not identify a specific threat to the species, and no population decline is documented in the sources consulted; as with other forest-stream fishes in the Congo basin, longer-term pressures such as deforestation and water-quality change in the wider basin are the kind of general concern that could eventually affect it, though the current status reflects no immediate conservation need.