Clarias camerunensis is a potential catfish for farming in Cameroon. In order to assess the parasitism of its monogeneans as a function of season and standard lengh, a study was conducted from April 2017 to April 2018 in Lép Mōōga stream, of the Nyong river watershed (Southern Cameroon). 179 specimens of C. camerunsis were sampled by angling through 5 consecutive seasons. The Prevalence, density, abundance of adults and larvae of the main Monogenean species as well as the condition coefficient K and gonadosomatic index of the female C. camerunensis were calculated. The prevalence of the adult Quadriacanthus sp. remained equal to or greater than 85% during this study. Its abundance was low and did not show any clear profile pattern; however, its variation peaked during the rainy season. The gonadosomatic index (GSI) and condition factor (K) of female C. camerunensis evolved in parallel and showed that this fish lays three times a year, during the short rainy, the short dry and the long rainy seasons. The profile of Quadriacanthus sp. larvae showed that this monogenean breeds all year with two peaks during the short rainy season (when the female hosts lay and are weak fry also are in the environment), and in January when hosts are more concentrated in low water. The physiological condition of the fish gradually improved as they grew, when the parasitic density decreased. To limit monogenean outbreaks in farming, this work recommands that fish caught in the wild should be placed in quarantine and dewormed before being exploited.