Two experiments were conducted to investigate the effect of coated amino acids.In Exp.1,crystal Lys,Met were coated with hardened lipid or gelatin,and the leaching loss in the water were 57%,14.3%,21.3% for crystal,hardened lipid coated and gelatin coated Lys,and 87.7%,19.0%,28.0% for crystal,harden lipid coated and gelatin coated Met.So the leaching loss of amino acid was significantly reduced by coating techniques.In Exp.2,0.23% Lys and 0.09% Met of crystal,hardened lipid coated and gelatin coated styles were added into basal diet(control group) containing 9% fish meal,to feed allogynogenetic crucian carp fingerling with body weight of(2.48 g.) After 6 weeks feeding,the growing rate of the four groups were 169.8%,173.3%,201.4%,200.2% for control group,crystal,hardened lipid coated and gelatin coated amino acids respectively.There was no effect of adding crystal amino acid on growing performance,but growing rate was improved by 18.6%,17.9%(P<0.05) and feed coefficient was decreased by 0.28,0.37(P<0.05) by adding hardened lipid or gelatin coated amino acid.Adding crystal or coated amino acid had no effect on muscle composition.Results above showed that the amino acid availability is significantly improved and the leaching loss in the water reduced by coating with hardened lipid or gelatin.