This study was conducted at fish laboratory affiliated to the department of animal production/ college of agriculture/ University of Anbar. The experiment lasted eight weeks (5 /Sep / 2022-31 /Oct / 2022) in Aquatic Recirculating System (ARS), to examine the appropriate effect of feeding common carp with different quantities of a certified commercial feed on hematological parameters, blood indicators, and cortisol hormone levels revealed that significant differences among the treatments. In the second treatment (T2), there was significant improvement (P≤0.05) in red blood cell count, hematocrit, hemoglobin, and white blood cell count compared to the other experimental treatments. Treatment four (T4) showed superiority in lymphocyte count, while treatment three (T3) exhibited higher values in both monocytes count and monocyte to lymphocyte ratio (P≤0.05). regarding the biochemical blood parameters, treatments T6, T5, T4, T2, and T1 demonstrated significant superiority (P≥0.05) over treatment three (T3) in terms of cholesterol, triglycerides, low-density lipoprotein, very low-density lipoprotein, ALT enzyme, and AST enzyme. However, high-density lipoprotein exhibited significant differences (P≤0.05) in treatments T5 and T4. As for cortisol levels, treatment two (T2) displayed significant superiority over the other experimental treatments (P>0.05).