RESUMO
Two different fish species [Oreochromis niloticus and Clarias gariepinus] were examined to investigate the correlation of parasitism between trichodinids and gyrodactylids. Four parasites were isolated from skin and gills of the examined fish: Trichodina centrostrigeata, [Basson et al. 1983, Trichodina compacta, Van As and Basson, 1989, Gyrodactylus rysavyi, Paperna, 1973 [28%] and Macrogyrodactylus clarii Gussive, 1961]. The highest prevalence [34.66%], intensity [23] and abundance [7.90] of parasitic infestation of C.gariepinus are shown in infected fish with gyrodactylids. A synergistic effect was noticed among such parasites studied herein. In field application, a special approach of such phenomenon [mixed infection] should be considered. In the present study, the clinical signs, prevalence, abundance of parasites and relative condition factor were reported and discussed