Genyomyrus is a monospecific genus of freshwater fish belonging to the family Mormyridae, the elephantfishes. The only species in the genus is Genyomyrus donnyi which is endemic to the Congo River. It reaches a length of about .
The fish is named in honor of Gen. Albert-Ernest Donny (1841âÂÂ1923), the president of the Société d'ÃÂtudes Coloniales, which sponsored the first major collection of fishes from the Congo.