Can individual feed conversion ratio at commercial size be predicted from juvenile performance in individually reared Nile tilapia Oreochromis niloticus

•Individual feed conversion ratio (FCR) was assessed in 30 male Nile tilapia reared individually over 210 days from 35 to 260 g.•FCR estimated over two weeks at juvenile stage (before 125 g or 250 dph) was significantly correlated with FCR measured over the 210 days of the experiment.•Faster-growing fish had a lower FCR.•Selecting individuals with the lowest FCR measured over a two-week period at juvenile stage would improve global FCR by around 1% per generation.