This work was carried out to detect behavioural response, performance and welfare of Nile tilapia fingerlings under different water temperatures. Fingerlings were reared in eight 90-L aquaria in duplicate for 60 days with 15 fish per aquarium at different temperatures (20 °C (group1), 24 °C (group 2), 28 °C (group 3), and 32 °C (group 4). The results showed that group 4 was higher in surfacing, surface swimming and aggressive behaviour than other groups. While, group 3 was higher in middle swimming behaviour and crossing test than other groups, but bottom swimming behaviour was higher in group 1 than other groups. Also final body weight of group 3 was markedly greater than other groups, finally, it is concluded that a temperature 28 °C is the optimum for achievement of Nile tilapia welfare due to high body weight, lowering in surfacing, scratching and aggressive behaviour, increasing the ability of Nile tilapia for practicing swimming behaviour.