The present study evaluated the effect of different energy levels (15.07, 15.91, 17.17, 18.00, and 19.68 kJ g-1 of diet) on isoproteic practical diets for Macrobrachium amazonicum during the nursery phase on the zootechnical performance and proximate composition of the whole body. Postlarvae with a mean weight of 0.043 ± 0.01 g were stored in 25 experimental units, at 150 animals per m2, in a completely randomized design with five treatments and five replicates. The post-larvae were evaluated at the end of the experimental period according to the pre-established performance parameters. The analysis of variance for regression (α = 0.05) allowed us to estimate that the maximum final weight was observed in the treatment with 16.74 kJ g-1. In contrast, the lowest apparent feed conversion was observed at the 16.43 kJ g-1 level. The best values were found in 17.29 and 17.50 kJ g-1, respectively, for the energy and protein retention rates. As the best fit of the equation was presented for the energy retention ratio (R2 = 0.63), which approached the treatment of 17.17 kJ g-1, this energy level is recommended in postlarvae diets.