Abstract: This paper studied chiral selective effect of quizalofop-ethyl enantiomer toxics on aquatic species. To that end, acute toxicity tests of quizalofop-ethyl enantiomers to B. rerio were conducted and variant ATPase activities of B. rerio under sublethal concentrations investigated. The study showed that although quizalofop-ethyl belonged to low-toxic pesticides, it was highly toxic to B. rerio. For Na⁺,K⁺-ATPase and Ca²⁺-ATP, the modes of quizalofop-ethyl enantiomers at both induction time and intensity were different. At 24 h and 48 h, the effects of quizalofop-ethyl on Ca²⁺-ATPase activity of B. rerio were not significantly different in all exposure and control groups. At 72 h, the exposure groups of 250 μg·L^-1 and 1 000 μg·L^-1 showed significant induction (P < 0.05). At 96 h, each exposure group showed an overall induction. Quizalofop-p-ethy1 showed significant induction of Ca2⁺-ATPase of B. rerio in each exposure group, except for 5 μg·L^-1 and 10 μg·L^-1 exposure groups at 24 h. While enzyme activity showed a declining tendency in 25 μg·L^-1 and 100 μg·L^-1 exposure groups after 72 h, it continued to rise in the other two exposure groups. The 250 μg·L^-1 and 1 000 μg·L^-1 exposure groups showed significant induction of Na⁺,K⁺-ATPase activity for B. rerio (P < 0.05) at 48 h. At 72 h, however, only the 1 000 μg·L^-1 exposure group showed significant induction. Quizalofop-p-ethy1 showed significant induction in 25 μg·L^-1 and 100 μg·L^-1 exposure groups at 24 h. After 48 h, enzyme activity began to increase significantly in each exposure group. At 72 h, enzyme activity showed a downward tendency in each exposure group. At 96 h, there was no significant difference between each set of the exposure and control groups. It was concluded that quizalofop-ethyl enantiomers had chiral selective effect on B. rerio.