Brycon amazonicus is an important freshwater migratory fish in the Amazon Basin. 29 Studies involving populations of B. amazonicus are of great importance for the conservation and 30 management of this species. We developed eight microsatellite loci and applied them to 31 investigate the genetic variation of 32 wild individuals from Catalan lake of the Black river. The 32 number of alleles per locus ranged from 6 to 17, with an average of 11.1. The observed and 33 expected heterozygosity values ranged from 0.654 to 0.906 (average 0.676) and from 0.527 to 34 0.887 (average 0.792), respectively. The value of f ranged from -0.018 to 0.239 (average 35 0.038). No significant linkage disequilibrium was detected. These microsatellite loci will 36 contribute towards studies of genetic diversity and conservation of B. amazonicus.