A new species of the genus Paeonodes Wilson, 1944 (Therodamasidae, Cyclopoida, Copepoda), P. lagunaris, is described from Tilapia melanotheron Rüppel, 1852, of the Sakumo-lagoon, Ghana, Africa. The new species is compared with the hitherto known two species of the genus Paeonodes and the relationship of the genus with euryhaline waters is discussed.