The replacement value of fermented millet for maize in the diets of Clarias gariepinus fingerlings reared in a recirculation system was determined. Five isonitrogenous diets were formulated to contain graded levels of fermented millet meal replacing 0, 20, 40, 60 and 80% of maize and fed to triplicate groups of fingerlings weighing 1.28± 0.2g. The feeding lasted for 12 weeks. Although, the feeds containing fermented millet were acceptable to the fish, the results showed that the diets significantly P<0.05 affected fish performance. There were significant reductions in feed conversion ratio and nutrient utilization efficiency with increasing fermented millet meals. However, highest percentage weight gain and lowest feed conversion ratio were observed on fish fed 20% replacement level, even though, growth depression occurred with increasing dietary levels of fermented millet (P>0.05).