Feeding trials with herbivorous and omnivorous Amazonian fishes

Fish of three species were fed on diets containing 30% total protein of which 0–95.5% was animal (fish meal) protein. Mylossoma sp. and Semaprochilodus theraponura showed the best growth rates (27 and 43.5% weight gain in 23 days) when only 25% of the protein was of animal origin, and Colossoma macropomum grew best (28.1% weight gain in 23 days) on a diet with no animal protein.Brycon melanopterum, an omnivore, grew well (50.5% weight gain in 29 days) on a diet containing 35% total protein of which 50% was of animal origin.