Hippopotamyrus is a genus of weakly electric elephantfishes in the family Mormyridae, part of the ancient bonytongue lineage (Osteoglossiformes) that also gives the aquarium hobby the arowanas. Several members carry the common name stonebasher, a nod to their habit of foraging along rocky and gravelly riverbeds. The atlas covers 5 species, ranging from about 5.5–12 in, found across West and Central African river systems in countries including Cameroon, Nigeria, Ghana, Guinea, Angola, and Namibia. Like all mormyrids, they carry a caudal electric organ that emits a weak, species-specific discharge, used for navigation and communication rather than for stunning prey, and a comparatively large, highly folded cerebellum that processes the electrosensory signal.
Hippopotamyrus species are mostly of scientific rather than hobby interest. Mormyrids are nocturnal, feed on aquatic invertebrates sifted from soft sediment or picked from rock crevices, and are notoriously sensitive to handling, cramped quarters, and poor water quality, which keeps most of the genus out of general circulation even though a handful of related elephantfishes (elephantnose fish among them) are staples of the specialist trade. The atlas records four species as Least Concern and one Not Evaluated, suggesting the genus is not under acute pressure at the continental scale, though data on some populations remain thin.
Taxonomically, Hippopotamyrus sits within a mormyrid radiation that has been repeatedly reshuffled as researchers use electric organ discharge waveforms alongside traditional morphology to sort species, a method that has proven unusually powerful in this family precisely because each species' pulse is so distinctive. That electrogenic signature is the main reason mormyrids remain an active subject of neuroscience and evolutionary research even where they rarely appear in a home aquarium.