<p>The alteration of water temperature influences fishery productivity. The aim of the present study was to investigate the impact of water temperature on the growth performance, gonad development, immunity, and antioxidant functions of hybrid red tilapia (<i>Oreochromis niloticus</i> × <i>Oreochromis aureus</i>). The experimental fish were reared at four different temperatures (22, 25, 28, and 31 ℃). The fish reared at 28 ℃ had the highest weight gain and the highest specific growth rate, but a lower feed conversion ratio. Increasing the water temperature to 28 ℃ promotes the development of the gonads of this fish; however, lower temperatures (22 ℃) can inhibit its development. The fish reared at 28 ℃ had the highest gonad somatic index (<i>P</i> &lt; 0.05). Malondiadehyde, lysozyme, and complement (C3) in the gills and liver of hybrid red tilapia (<i>O. niloticus</i> × <i>O. aureus</i>) were significantly decreased at 31 ℃, indicating the immune system was influenced at a higher temperature. However, the total antioxidant capacity, superoxide dismutase, and glutathione in the gills and liver of the fish were significantly higher (<i>P</i> &lt; 0.05) at rising temperatures. The fish reared at 25 ℃ showed better liver health. We conclude that thermal stress may increase oxidative stress and reduce immune function in red tilapia, leading to impaired fish growth, and reproduction. Knowledge of the effects of temperature on fish species is critical for sustainable fishery management, and it may improve the production of these species and contribute to genetic breeding programs.</p>