Five treatments including control and four concentrations of water soluble fraction (WSFs) crude oil (5 ppm, 6 ppm, 8 ppm and 10 ppm) were made. Triplicate and ten fish of red tilapiawith an average weight of 8g ± 1.5 were incubated for 96 hours. The 96 hours LC₅₀ was determined (5.25ppm). Histopathological examination of the fish was made for liver, gills, kidney, male gonad and female gonad. Liver showed congestion of blood vessels and hepatic sinusoids with focal necrotic changes of hepatocytes. Gills showed congestion of blood vessels, hyperplasia and adhesion of secondary gill lamellae. Kidney showed congestion of blood vessels and degeneration of renal tubules. Male gonad showed degeneration and necrosis of some seminiferous tubules, edema and severe reduction in all spermatogenic stages and degeneration and Female gonad showed severe necrosis of developmental stages of oocytes along with degenerated mature ripped oocytes in WSFs treated fish compared to control group.