Abstract: The relative abundance of Bonga, Ethmalosa fimbriata, a clupeid schooling pelagic trash fish in the Nigerian Coastal waters coupled with the low price because of its numerous tiny bones promotes its use for fish meal as an alternative to the expensive conventional fish meal. This study aims to test the suitability of using processed Bonga (fish meal) and determining its level of supplementation with conventional fish meal in promoting Clarias gariepinus fingerlings growth. Twentyfive (25 kg) kilograms fresh weight Ethmalosa fimbriata was ovendried for 45 h at 80-90°, ground, sieved into fine powder and supplemented into 6 isonitrogenous diets each of 38% crude protein level (0, 20, 40, 60, 80 and 100%) diets. The Crude Protein (C.P) level of the processed Bonga fish meal was 57.79%. A twelve week nutritional experiment was carried out in which Ethmalosa fimbriata fish meal based diets were fed to (90) ninety fingerlings of Clarias gariepinus distributed in 6 graduated plastic bowls at the rate of 15 fingerlings per bowl with a weight range of 2.40 gm-2.51 gm/fingerling. The 6 isonitrogenous diets (0, 20, 40, 60, 80 and 100%) were fed ad libitum twice daily at 09.30 and 16 h, respectively after daily changing of water in the plastic bowls. Analysis of variance (ANOVA) for the growth and nutrient utilization parameters showed significant (p<0.05) variations for specific growth rate, protein efficiency ratio, food conversion ratio, productive protein value, feed intake and gross food conversion efficiency. The highest Specific Growth Rate (SGR) of 1.95 least Food Conversion Ratio (FCR) of 2.02 and the highest average daily growth rate (DGR) 0.120 gm/day showed the 40% diet as the best. This was closely followed by the 20% diet with SGR (1.90), FCR (2.02) and DRG (0.115). While the least grow out of Clarias gariepinus fingerlings was recorded for the 100% diet with SGR (1.37), FCR (2.97) and average DRG (0.067). This study shows that supplementation of Bonga (Ethmalosa fimbriata) fish meal of C.P 57.79% with the conventional Danish fish meal (of C.P 72.00%) is best at the 40% level of supplementation while 100% supplementation of Ethmalosa fimbriata fish meal will not give the best growout result for Clarias gariepinus.