||In Niger River, the family of Mormyridae, also called elephant fishes, is one of the most speciose taxa that constitutes an economically and commercially important fishery resource in tropical Africa. From February 2015 to July 2016, Mormyrids fishes were collected monthly with gill net, cast net and seine. Eleven (11) Mormyrid fish species belonging to nine (9) genera have been recorded. The genus Mormyrus was the most speciose with 3 species Mormyrus macrophthalmus, Mormyrus rume, and Mormyrus hasselquisti. Because most Mormyrids are intolerant to pollution, less degraded sites such as “Gaya” and “Money” villages harbor the highest diversity, 11 and 10, respectively, whereas degraded locations such as “Sota stream” and “under Benin-Niger Bridge’ were less diverse with 5 and 4 Mormyrid species. Major threats to Mormyrid fish species were climate changes, pollution, uses of detrimental fishing methods, overfishing and the non-respect of fishing regulation. A holistic management
scheme of the Niger River in Benin is required for a sustainable exploitation of the Mormyrid fishes.