The main aim of this study is to determine the effect of fish stocking density and aeration rate on the performance of mint (Mentha spicata L.) and Nile tilapia (Oreochromis niloticus) in aquaponic system. To achieve that, the effects of different fish stocking densities (5, 10 and 15 kg m^-3) and different aeration rates (0.2, 0.3 and 0.4 g O₂ per kg fish.hr) on plant growth and fish biological parameters. The results indicated that, the root and shoot length of mint plant increases with increasing fish stocking density, aeration rate and plant age. The highest values of root and shoot length (25.75 and 32.40 cm) were found at 15 kg m^-3 fish stocking density and 0.4 g O₂ kg^-1 of fish.hr^-1 aeration rate. The highest values of fresh and dry weight of shoot (132.71 and 26.05 g plant^-1) were found at 15 kg m^-3 fish stocking density and 0.4 g O₂ kg^-1 of fish.hr^-1 aeration rate. The total weight gain, fish growth rate, specific growth rate feed conversion ratio and feed efficiency ratio of tilapia fish decreases with increasing fish stocking density and decreasing aeration rate. The highest values of the total weight gain, fish growth rate, specific growth rate feed conversion ratio and feed efficiency ratio of tilapia fish (40.83 g, 1.36 g day^-1, 1.60 % day^-1, 1.11 g feed g^-1 fish and 1.18 g fish g^-1feed) were found at 5 kg m^-3 fish stocking density and 0.4 g O₂ kg^-1 of fish.hr^-1 aeration rate.