Taxonomy & naming
Pollimyrus petherici was described by the ichthyologist George Albert Boulenger in 1898, originally as Gnathonemus petherici. It belongs to the family Mormyridae — the elephantnoses and mormyrids — within the order Osteoglossiformes, the bonytongue fishes, one of the oldest surviving lineages of teleosts. Boulenger described a large share of the mormyrid species known from Africa at the turn of the twentieth century, typically working from museum specimens rather than fieldwork of his own.
The genus Pollimyrus was not erected until 1971, when the ichthyologist Jacques Taverne separated a group of smaller-bodied mormyrids from the broader genus Marcusenius; Boulenger's species was moved into it along with its congeners. Eschmeyer's Catalog of Fishes lists Pollimyrus petherici as a valid species. The precise type locality of the original description is not confirmed in the sources reviewed for this account, though the species epithet ties the fish to the Nile explorer John Petherick (see Etymology, below).
Morphology
No confirmed maximum-length measurement for Pollimyrus petherici was found in the sources reviewed for this account. Every described species in the genus Pollimyrus is a small mormyrid, most maturing well under 6 in, but no figure specific to this species is substituted here.
As in every mormyrid, Pollimyrus petherici carries an electric organ near the base of the tail that produces a weak, pulse-type discharge. Electroreceptors spread across the skin read the resulting field, a sense mormyrids rely on heavily in murky or nighttime water where eyesight offers little. Mormyrids also carry one of the highest brain-to-body mass ratios of any vertebrate group, with an enlarged cerebellum given over to processing this electrosensory stream. No discharge waveform specific to Pollimyrus petherici has been published in the sources reviewed here.
Habitat
Confirmed locality records for Pollimyrus petherici were not available for this account. The species epithet honors John Petherick, a nineteenth-century explorer and collector active on the White Nile, which points toward a Nile-basin origin for the type material — but that connection is historical rather than a verified distribution record, and no country or drainage is assigned here on the strength of a name alone.
Mormyrids in general favor slow, turbid, structure-rich water — backwaters, flooded margins, and river reaches with cover from roots or submerged vegetation — where an electric sense outperforms sight. Whether Pollimyrus petherici follows that pattern specifically has not been documented, and water-chemistry data for the species is likewise absent from the sources reviewed.
Feeding
No diet study specific to Pollimyrus petherici was found in the sources reviewed for this account. Mormyrids as a group are bottom-foraging invertebrate feeders, using electrolocation to find insect larvae, worms, and small crustaceans hidden in mud, silt, and leaf litter before taking them with a quick strike of the mouth. This species is presumed to feed the same way, though that has not been confirmed for it specifically.
Mating
Courtship behavior has not been described for Pollimyrus petherici. In mormyrids generally, the electric organ discharge does more than aid navigation — its pulse pattern is often species- and sex-specific, and it is thought to figure in mate recognition and shoal cohesion. The well-studied congener Pollimyrus isidori produces audible grunts and moans alongside its electric signal during courtship, a combined acoustic-electric display documented in detail by researchers including Christopher Crawford. That behavior has not been shown in Pollimyrus petherici, however, and is not assumed here.
Breeding
Breeding has not been recorded for Pollimyrus petherici, in the wild or in captivity, in any source reviewed for this account. Spawning behavior, egg or larval description, and parental care are all unknown for this species. As with most small African mormyrids, any account of its reproduction would currently be speculation, and none is offered here.
In the aquarium
Pollimyrus petherici has essentially no documented presence in the aquarium trade; no keeping reports or husbandry notes specific to this species were found in the sources reviewed here. What follows describes general practice for small mormyrids rather than any track record established for this particular fish.
Mormyrids as a group need a soft substrate for probing, ample cover, dim lighting, and stable, clean water with minimal turbidity; the family is also known for unusual sensitivity to some medications, which argues for gradual acclimation and conservative dosing whenever one is treated for disease. They typically refuse dry foods and need live or frozen invertebrate foods such as bloodworm and brine shrimp, best offered after the lights dim to match their nocturnal foraging habit. None of this has been verified specifically for Pollimyrus petherici, but it reflects standard practice across the family it belongs to.
Conservation
Pollimyrus petherici does not appear to carry a current IUCN Red List assessment, based on the sources reviewed for this account. No population trend, range size, or species-specific threat has been documented.
Many small, narrowly distributed African mormyrids have never been formally assessed. General pressures on African freshwater systems — habitat degradation, siltation, and declining water quality — are the kind of long-term risk that could affect any of them, but none has been documented specifically for this species, and none is asserted here.