Taxonomy & naming
Pollimyrus guttatus was described by the American ichthyologist Henry Weed Fowler in 1936. It belongs to the family Mormyridae — the elephantnoses and mormyrids — within the order Osteoglossiformes, the ancient bonytongue lineage of teleost fishes. The genus Pollimyrus itself was not established until 1971, when the ichthyologist Jacques Taverne split a group of small-bodied mormyrids away from the broader genus Marcusenius; Fowler's description predates that split, and the parenthetical authorship reflects a later move into Pollimyrus rather than an original placement there. The species' original genus and any subsequent synonymy are not confirmed in the sources reviewed for this account.
A 2025 morphometric synthesis of the genus Pollimyrus, drawing on comparative body-shape measurements across its member species, examined and confirmed the taxonomic validity of Pollimyrus guttatus within the genus. FishBase and the Catalog of Fishes both list Pollimyrus guttatus as the current, accepted combination.
Morphology
Pollimyrus guttatus is one of the smallest fish in a genus already defined by small body size, reaching a documented maximum of only about 2 in in total length — smaller even than the modestly sized congener Pollimyrus castelnaui (about 3 in standard length), though the two figures use different length conventions and are not perfectly comparable. Even allowing for that, guttatus is among the tinier species in the entire family Mormyridae.
As in every mormyrid, an electric organ in the caudal peduncle produces a weak, pulse-type electric field, read through electroreceptors spread across the skin and used to build a moving picture of the surrounding water where eyesight is of limited use. Mormyrids carry some of the highest brain-to-body mass ratios of any vertebrate group, with an enlarged cerebellum devoted to processing this electrosensory information. No electric organ discharge waveform or other body-plan detail specific to Pollimyrus guttatus, beyond its small overall size, has been published in the sources reviewed for this account.
Habitat
Pollimyrus guttatus is documented from Cameroon and the Central African Republic, with a specific locality recorded near Kribi in the Kienke River of southern Cameroon. It is a purely freshwater, bottom-associated (demersal) fish; beyond that, no detailed habitat description — river type, vegetation, or water flow — has been published for this species specifically, and its fuller distribution across the Central African Republic is not tied to a named river system in the sources reviewed here.
No temperature or water-chemistry measurements specific to Pollimyrus guttatus have been documented. General mormyrid care literature describes the family as favoring warm, structurally complex water from the mid-20s to high-20s °C with neutral to slightly acid chemistry, but that reflects broad husbandry guidance for the family rather than data recorded for this species or its native rivers.
Feeding
No feeding study specific to Pollimyrus guttatus has been published. Mormyrids as a group are bottom-foraging invertebrate feeders, using electrolocation to find insect larvae, worms, and small crustaceans in mud, silt, and leaf litter before taking them with a quick strike of the small mouth. This species is presumed to feed the same way, though that has not been confirmed directly for it.
Mating
Courtship in Pollimyrus guttatus itself has not been documented. In the best-studied congener, Pollimyrus isidori, males are known to combine their electric organ discharge with acoustic signals — grunts produced by vibrating the swim bladder — during courtship, and a 2025 morphometric review of the genus references this pattern of combined acoustic and electric signaling in Pollimyrus more broadly. Whether Pollimyrus guttatus produces sound or uses its discharge in courtship the same way has not been observed or reported, and it is not assumed here.
Breeding
Breeding has not been recorded for Pollimyrus guttatus, 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 Central African mormyrids, any account of its reproduction beyond this would be speculation, and none is offered here.
In the aquarium
Pollimyrus guttatus 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. At a maximum size of about 2 in it would rank among the smallest mormyrids ever considered for a tank, small enough that only the gentlest, similarly diminutive tankmates could reasonably share space with it.
What follows, then, describes general mormyrid practice rather than any track record established for this particular fish: a soft substrate for probing, dim lighting, ample cover, and stable water with low turbidity. Mormyrids as a family are known for unusual sensitivity to poor water quality and to certain medications — copper-based treatments in particular are frequently fatal to them — which argues for gradual acclimation and conservative dosing. They typically refuse dry foods and need live or frozen invertebrate foods such as bloodworm and finely sieved brine shrimp, offered after the lights dim to match a nocturnal foraging habit. None of this has been verified specifically for Pollimyrus guttatus.
Conservation
The IUCN Red List assesses Pollimyrus guttatus as Data Deficient, based on a 2022 assessment — meaning there is not enough information on its population, range, or trend to judge its extinction risk, a status distinct from a clean bill of health. Its known range is narrow: a coastal river system in southern Cameroon, plus a broader and less precisely documented occurrence in the Central African Republic.
No species-specific threats have been documented. Small, narrowly distributed mormyrids in Central African drainages face the same general long-term pressures as other freshwater fish in the region — habitat degradation, siltation, and water-quality decline — but none of these has been tied specifically to Pollimyrus guttatus in the sources reviewed for this account.