Heteromormyrus is a small genus of African elephantfishes (family Mormyridae) from south-central Africa, recorded in the atlas from Angola, the Democratic Republic of the Congo, Botswana, Malawi, Mozambique, Namibia, Zambia and Zimbabwe. Like other mormyrids, its members are weakly electric fish, generating and sensing a low-voltage field around the body to navigate and locate prey in murky or nighttime water, a sense that largely replaces vision in their day-to-day behaviour. The atlas covers 4 species, from about 4–7 in, including Heteromormyrus ansorgii, known by the common name slender stonebasher — a name shared with several related mormyrid genera whose common feeding habit is dislodging invertebrates from rocks and gravel rather than probing soft mud with an elongated snout.
Heteromormyrus is essentially a scientific-interest genus rather than an aquarium-trade one; mormyrids in general are demanding, electroreception-dependent fish that fare poorly under bright light or in tanks with strong electrical interference, and this genus has little to no established hobby presence. Conservation data remain limited: the atlas tally runs three Least Concern to one Data Deficient, suggesting the assessed species are not currently considered at risk, though thorough surveys across this genus's African river systems are sparse.