Abstract: To study the effects of fatty acids on zebrafish (Danio rerio), three diets with isonitrogenous and isolipidic nutrients of basal diet (control group), 7 g/kg n-3HUFA (Highly unsaturated fatty acid) (HUFA group) and 10 g/kg MCFA (Medium chain fatty acid) (MCFA group) were formulated to fed a total of 360 healthy four months old parent zebrafish including 180 male (0.59±0.06) g and 180 female (0.36±0.05) g fish that were randomly divided into three groups (triplicate per group) for a 90 days trial. The fatty acid composition of gonad, fecundity and larvae survival rate were used to assess the effects of fatty acids. The results indicated dietary fatty acids were effectively incorporated into ovaries of female fish with high coefficients that were all more than 0.8. EPA and DHA content in ovary tissue of HUFA group were higher than those in MCFA group and control group (P<0.05), and there was no significant diffe-rence between MCFA group and control group. Oleic acid was significantly lower in HUFA group than that of MCFA and control groups (P<0.05), and there was no significant difference between MCFA group and control group. Linole-nic acid content in HUFA group was higher than that in MCFA group (P<0.05), and linolenic acid content in the two groups were higher than that of control group. Gonadosomatic index, absolute fecundity, relative fecundity of weight and body length in HUFA group and MCFA group were significantly higher than those of control group (P<0.05) and the fecundity in HUFA group was significantly higher than that in MCFA group (P<0.05). For the mating experiment using female fish fed with different diet, absolute egg production, relative egg production rate of female fish and survi-val rate of larvae in HUFA group were significantly higher than that of MCFA group, and these two groups were significantly higher than control group (P<0.05). For the mating experiment using male fish fed with different diets, fertility rate in HUFA group was significantly higher than that in MCFA and control groups (P<0.05). The present result showed that the fatty acid composition in diets regulated fatty acids composition in ovaries of female fish, the reproduction performance of female fish and the survival ratio of the larvae with the better beneficial effects for HUFA compared with MCFA.