The protein source affects growth and body composition of fish. Fishmeal is an important source of protein in the diets of carnivorous fish species because of its high protein quality and palatability. However, fishmeal is quite expensive and can substantially increase feed costs. Total or partial substitution of fishmeal with less expensive plant and animal protein feedstuffs may help to reduce feed costs, although these sources may be lower in digestibility, palatability and essential amino acids (Robinson and Li 1996).