Taxonomy & naming
Petrocephalus zakoni was described in 2010 by Sébastien Lavoué, John P. Sullivan and Matthew E. Arnegard as part of a broader revision of the genus Petrocephalus. It belongs to the family Mormyridae — the elephantnoses and mormyrids — within the order Osteoglossiformes, the ancient bonytongue lineage of teleost fishes. FishBase lists type localities for the species that include the Lékoli River within Odzala National Park, the Pool Malebo stretch of the Lower Congo, and the Sangha River basin, placing its original collections within the Congo River system of Central Africa.
The species epithet honors Harold H. Zakon, a University of Texas neuroscientist recognized for research on electroreception and communication in mormyrid fishes. A later molecular phylogenetic study found haplotypes of the nominal species Petrocephalus leo nested within those of P. zakoni, pointing to a close relationship between the two that has not been resolved into a formal taxonomic revision. As with many Petrocephalus described in this period, reliable field identification within the genus often depends more on the species-specific electric organ discharge than on external appearance alone.
Morphology
Petrocephalus zakoni is one of the smaller members of its genus, reaching a maximum recorded length of about 3.5 in standard length. FishBase describes the species as bearing a dark, saddle-shaped blotch near the base of the dorsal fin and a crescent-shaped mark at the base of the tail, set against the silvery, laterally compressed body typical of the genus. Like other Petrocephalus, it has the short, blunt head and small, low-set mouth that separate the genus from the long-snouted, chin-barbelled Gnathonemus.
As in all mormyrids, an electric organ in the caudal peduncle generates a weak, pulse-type discharge that the fish reads through electroreceptors spread across its skin. In genus revisions such as the one that described P. zakoni, this discharge is frequently the most reliable character for separating superficially similar Petrocephalus species, since external pigmentation and body proportions overlap heavily from species to species.
Habitat
Petrocephalus zakoni is native to the Congo River basin of Central Africa, recorded from the Central African Republic, the Republic of Congo, and the Democratic Republic of Congo. FishBase lists collection localities that include the Lékoli River inside Odzala National Park, the Pool Malebo stretch of the Lower Congo, and the Sangha River basin, spreading the species across a wide reach of the central Congo system rather than a single isolated site.
FishBase classes it as a benthopelagic freshwater fish of tropical rivers, consistent with other Petrocephalus, which typically occupy slow-moving, structure-rich stretches of river and forest floodplain. Specific temperature and pH figures have not been published for this species; Congo basin rainforest rivers of this kind generally run warm and on the soft, acidic side, but that is a regional expectation rather than a measured value for P. zakoni.
Feeding
No species-specific dietary study has been published for Petrocephalus zakoni. Like other members of the genus, it is presumed to be a benthic invertebrate feeder, using its electric sense to locate small prey such as insect larvae and other invertebrates hidden in sediment and leaf litter — the feeding style documented across Petrocephalus and Mormyridae generally.
Aquarium-care literature on mormyrids as a family recommends live and frozen invertebrate foods such as bloodworm and brine shrimp, since these fish rarely take dried or flake food. No captive feeding record specific to P. zakoni exists to confirm this pattern for the species itself.
Mating
No courtship or mating behavior has been documented for Petrocephalus zakoni, in the wild or in captivity. In mormyrids generally, the electric organ discharge is thought to contribute to mate recognition and shoal cohesion alongside its role in navigation, but that has not been studied in P. zakoni specifically, and it would be a mistake to present it as established fact for this species.
Breeding
Breeding in Petrocephalus zakoni has not been recorded in the wild or in the aquarium. As with the great majority of Petrocephalus species, no spawning account, egg description, or larval record has been published for this fish, and it is not known to have been bred in captivity.
In the aquarium
Petrocephalus zakoni is essentially absent from the aquarium trade. Coverage of elephantnose fishes in the hobby press lists it among the many small Petrocephalus species that are rarely, if ever, offered for sale, well behind the far more commonly traded Peters's elephantnose, Gnathonemus petersii.
Should specimens appear in the hobby, general mormyrid husbandry would apply: a soft substrate for probing, dense cover and dim lighting to suit a shy, electrosensory fish, stable water quality, and a diet of live or frozen invertebrate foods rather than flake. Mormyrids as a group are known to be sensitive to poor water quality and to some common medications, so cautious acclimation matters more than with typical community fish. None of this should be read as an established care record for P. zakoni itself — the species has no documented aquarium history to draw on.
Conservation
Petrocephalus zakoni has not been evaluated by the IUCN Red List. No conservation assessment, population trend, or threat analysis has been published for the species.
It is documented across a broad stretch of the Congo basin spanning three countries, including sites within the protected Odzala National Park, which suggests at least part of its range receives some habitat protection. General pressures on Congo basin rivers — deforestation, siltation, and small-scale fishing pressure — are the kind of long-term concerns that could eventually affect the species, but in the absence of a formal assessment this is background context rather than a stated risk.