Four isonitrogenous (34.6 g kg^-1 of crude protein) and isoenergetic (19.5MJ kg^-1 gross energy) were formulated. Each diet was supplemented with 0 (Control), 0.5 g/ 100 g(T1), 1 g/ 100 g (T2) and 1.5 g/ 100 g (T3) dried Cyclotella spppowder. Nile tilapia broodstock were used in the present experiment 32 broodstocks (24 females + 8 males). Broodstock were sexed and transferred to conditioning 8 concrete ponds (3×1×1 m), and kept separately where, males stocked in 4  concrete ponds at stocking of 2 males in each pond also, the same  was conducted for females while, stocked at 6 females in each pond in two replicate. No significant differences were found in growth performance and feed utilization for male and female fed diets supplemented with Cyclotella spp for30 days before mating. The best condition factor and gonadosmoatic index were recorded in T3, which supplemented with 1.5% Cyclotella spp < em>. The higher pH and sperm motility value were detected in male of T3 and T2 with insignificant differences between treatments, while the lowest one was observed in control. The highest value of absolute fecundity, relative fecundity and system productivity were obtained in T3.