A feed for fishes and shellfishes prepared from lees of squeezed plants as a plant waste and having a high efficiency of feeding. The feed comprises a matrix material containing the product of microbial fermentation of the lees or the product of pulverization thereof and a mixture of lower amino acids (A) bearing two to three carbon atoms and higher amino acids (B) bearing at least four carbon atoms in a molar ratio, A/B, of 1 to 40.