The tambaqui (Colossoma macropomum) is a fish of primary importance in South American aquaculture, principally in the Amazon region and has a particularly unique diet in the wild. Oryza spp, or Wild rice as it is commonly known, is native to the floodplains of muddy rivers in the Amazon region. The aim of this study was to analyze the physical performance and the effects of dietary levels of Oryza spp. via the hematological parameters, total food intake, conversion efficiency, growth ratio and swimming performance of this fish. Diets containing 45% Oryza spp. induced the best performance in tambaqui. Diets containing 15% and 30% did not affect these indices, thus indicating that this amount of Oryza can be used as an alternative energy source for this important species within Brazilian aquaculture.