The aim of this study was to investigate the effective concentration of ethanolic extract of bee pollen on liver, spleen and heart tissues of fish. Bee pollen extract in various concentrations (0.5, 2.5, 5, 10, 20 and 30 ppm) was administered to fish for 96 h under aquarium conditions. The malondialdehyde (MDA) levels, total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI) and levels of total free sulfhydryl groups were investigated in liver, spleen and heart in fish samples. MDA levels in liver, spleen and heart tissues of various concentration groups (2.5, 5, 10, 20 and 30 ppm) decreased (p<0.05) compared to the control group. The highest value of TAS (P<0.05) and the lowest value of TOS (p<0.05) occured in liver and heart tissues of 10 and 20 ppm concentration groups. The lowest levels of OSI were recorded in liver and heart tissues of 10, 20 and 30 ppm concentration groups compared to control group (p<0.05). The highest values of total sulfhydryl groups were recorded (p<0.05) in all tissues of 10 and 20 ppm groups compared with that in the control group. Finally it was observed that in liver, spleen and heart tissues of fish, the antioxidant effects of ethanolic extract of bee pollen depended on concentrations.