The study determined the LC50 of the dispersant OSD Seacare, used in Nigeria. The LC50 of the mixture of the dispersant and the Nigerian Bonny light crude oil on the fingerlings of an indigenous and most farmed fish, the African catfish (Clarias gariepinus) was determined. The synergistic effect of OSD Seacare on bonny light crude oil using the African catfish (Clarias gariepinus) was also determined. The study also determined the impact of the dispersant and crude oil mixture on the growth, liver and kidney of the African catfish (Clarias gariepinus). The work measured the impact of the dispersed oil on the gills of Clarias gariepinus at the various sublethal concentrations. The bioconcentration factors and depuration rates of PAHs in the fish exposed to the different sublethal concentrations were also determined.