The Couffo basin is not well known, and neither are its aquatic living resources, such as fish fauna, which are subjected to high exploitation rates. The objectives of this study were to establish length-weight ratios (LWRs) and length-length ratios (LLRs) for the most important species in the catches and those of certain economic value. A total of 12,191 specimens belonging to 40 commercial species of actinopterygian fishes were caught with several fishing gears and methods between February 2018 and March 2021. Allometric coefficient