Cassava is the fifth globally most important staple crop but like most plant feed ingredients are deficient in vitamin A (VA). Genetically engineered provitamin A β-carotene, (proVAC) cassava may be plausible source of vitamin A and energy to those fishes that can tolerate high carbohydrate diet. The β- carotene in genetically improved cassava root can be converted by fish to vitamin A. We produced five isonitrogenous and isocalorific diets (feed 1 to feed 5 ) with non fermented proVAC cassava and β-carotene inclusion levels of F1, 20%,114.6 µg g^-1 ,F2, 15%,85.95 µg g^-1 ,F3, 10%,57.3 µg g^-1 , F4, 5%, 28.65 µg g^-1 and F5 0%,0 µg g^-1 . African catfish Heterobranchus longifilis of average weight 1.69±0.5g, were stocked at 10 fish per 15L aquaria in 3 replicates per feed type and fed ad libitum for 10 weeks. The growth and effects of the dietary provitamin A carotene on the fish were examined. Specific growth rate was best for catfish fed F4, 4.95 ± 0.10 % day^-1 and reduced with increasing inclusion of proVAC cassava. The FCR was best and same for those fed 0% cassava F5, 1.72 ± 0.06 and 5% cassava F4, 1.73 ± 0.03, decreasing with reducing inclusion of proVAC cassava. The VA content of the catfish was highest for those fed with 20% 114.6µg g^-1 proVAC (F1). Catfish VA content increased with increasing inclusion of proVAC cassava and β-carotene values of the diets. Gut length significantly reduced with increasing ProVAC cassava. Inclusion of proVAC cassava should not be above 5% in diets of Heterobranchus longifilis.