Brycinus longipinnis is native to the western coastal regions of Africa from The Gambia to Democratic Republic of the Congo. It is found in the upper and lower reaches of big rivers and also in estuarine mixohaline waters. It is the only Brycinus species also to penetrate small rivers and streams.
Brycinus longipinnis will grow to at least five inches (12.5 cm) long although most specimens are smaller than this. The populations in the small streams are smaller fish than those in the big rivers. Although it is essentially a freshwater fish, Brycinus longipinnis will live in brackish estuarine waters.
Brycinus longipinnis eats a wide range of animal and vegetable matter, including insect larvae, crustaceans and some algae.