Wikipedia
Mormyridae
The family Mormyridae, sometimes called "elephantfish" (more properly freshwater elephantfish), are freshwater fish in the order Osteoglossiformes native to Africa. It is by far the largest family in the order with around 200 species. Members of the family are popular, if challenging, aquarium species. These fish are also known for having large brain size and unusually high intelligence.
They are not to be confused with the marine and brackish water callorhinchid elephantfish (family Callorhinchidae) of south hemisphere oceans.