In this study, the effecs of centary oil (Hypericum perforatum) on growth performance and some blood parameters of fry common carp (Cyprinus carpio) were evaluated. For this purpose, 3 different experimental diets containing rate of 0 g/kg (SKY0), 5 g/kg (SKY5) and 10 g/kg (SKY10) centaury oil were prepared. The study consisted of 3 repetitions for each group with 3.07 +/- 0.02 g fry and in 40 L plastic tanks as 30 fish per aquarium for 60 days. At the end of the experiment, the live weight gain and specific growth rate of the fishes fed with SKY5 fed group were significantly different from the other groups (p <0.05). It was observed that centaury oil in different ratios added to the diet did not cause any difference in the amount of red blood cells, hemoglobin and hematocrit in fish (p>0.05). In serum biochemical findings of fish, St. John's Worth oil was found to be a significant difference among the groups (p<0.05). As a result of the present study, that can be suggested the centaury oil can use in common carp diets at the rate of 5 g/kg without adverse efects on growth performance, hematological and serum biochemical parameters of fish.