This research was done to find the effect of spirulina (Arthospira platensis) on some physicochemical parameters in common carp (Cyprinus carpio). Fish with an initial body weight of 510.3±7.02g were collected from a private farm in Khank Township, Sumeel District, Duhok Government, Iraq. Fish were separated into two groups (twenty fish in each group), the carp in the first group fed on pellets alone while the second fish group fed on pellets with 10 mg/kg spirulina for 90 days. Results; there was no significant change of morphological parameters in fish feeding with commercial spirulina pellets compared with control fish group. In contrast, a significantly increases in the average daily and total gain, the specific growth rate and the condition factor in the fish fed commercial pellets with spirulina compared with control fish. Regarding the complete blood pictures, a significantly higher of the red and white blood cells, hemoglobin, and hematocrit observed in spirulina fish compared with the first group while a significant decreases of the mean corpuscular hemoglobin, mean corpuscular volume and mean corpuscular hemoglobin concentration in fish feds commercial pellets with spirulina. Furthermore, highly significant differences were seen among lipid profile parameters with exception of significantly reduce of low-density lipoprotein in fish fed diets with spirulina. Moreover, significant increases levels of the total protein and globulin were observed in spirulina fish compared with the first group while a reduction of albumin level was noted. In addition, a significant reduction of the level serum enzyme activities of fish fed with commercial pellets with spirulina compared with the control fish. This study concludes that the diet with spirulina supplementation has a crucial roles in growing performances and hematological and biochemical parameters in fish.