In Nile tilapia, Oreochromis niloticus, dietary dry Golenkinia longispicula supplementation (0.0, 5, 10 and 15 g kg-1 diets) was utilized to improve growth, feed efficiency, and hematologically related gene expression. For a period of ninety days, fingerlings weighing 3.29 ± 0.16 g at hatching were randomized and placed in triplicate into twelve fiberglass tanks measuring 0.5 m3 and holding 250 L of water each for each treatment. After 90 days of the feeding trial, the results demonstrated final body weight (FBW), weight gain (WG), specific growth rate (SGR), and feed conversion ratio (FCR) were significantly (P < 0.05) improved by a diet contained 15 g kg-1 G. longispicula. The highest hematocrit (Hct), hemoglobin (Hb), red blood cells (RBCs) levels were detected in the fish-fed diet that had 15 g of G. longispicula kg-1. The values of growth hormone (GH) and growth hormone receptor were upregulated fish fed a diet that included 15 g kg-1 G. longispicula kg-1 diet.