This study provided was carried out with the objective of determining the ideal stocking density for the rearing of tambaqui juveniles Colossoma macropomum, a fish native to the northern region of the Brazil that has favorable zootechnical and market characteristics for the development of regional fish farming. For this purpose, three stocking densities (100 fish per m³, 200 fish per m³ and 300 fish per m³) in triplicate, were evaluated in a completely randomized design for 68 days. The fish, with an initial average weight of 077 ± 0.01 g, were fed daily according to the feeding rate. Regarding the results, the growth variables showed a significant difference (P> 0.05), except for survival and feed conversion, with the treatment with animals stored in 100 fish per m³ showing the best performance between treatments. The stocking density of tambaqui juveniles is inversely proportional to weight gain, specific growth rate and average feed consumption. Therefore, it is suggested to cultivate the tambaqui juveniles in a water recirculation system at the stocking density of 100 fish per m³.