Although high temperature treatment decreased survival and inhibited the growth of exposed fish during the early treatment period, the fish later started to increase food consumptions and growth rate when they were maintained at control temperature. The average growth was significantly increased in sterile fish at the end of the experiment. Sexual maturation in Nile tilapia usually starts at 4–5 months after hatching. The significant growth difference in the present study corresponded with the onset of sexual maturation. At this stage, the metabolizable energy that was supposed to be utilized for gonadal development was used for somatic growth as described for several species of fish (Basavaraja and Antony, 1997; Dygert, 1990; Majhi et al., 2009b; Rijnsdorp, 1990). On the other hand, gonadal somatic cells are capable of producing growth hormone and the gonad may act as an endocrine organ that produces growth hormone in fish (Bhatta et al., 2012)