This study was carried out to compare the acute toxicity(96hr) of 13 chemicals to carp (Cyprinus carpio L.) and israeli carp (Cyprinus israeli carpio L.) and the activities of acetylcholinesterase (AchE) and glutathione S-transferase (GST) in israeli carp exposed to five insecticides (diazinon, malathion, carbofuran, cartap, methomyl). $LC_{50}$ values of acute toxicity of the chemicals to israeli carp were endosulfan 0.0061ppm, captafol 0.041ppm, chlorothalonil 0.073ppm, butachlor 0.48ppm, captan 0.14ppm, carbofuran 1.13ppm, cartap 1.15ppm, diazinon 1.35ppm, nitrofen 3.72ppm, methomyl 4.39ppm, propanil 10.61ppm, malathion 11.78ppm and isoprothiolane 12.81ppm. The acute toxicity of endosulfan 0.0061ppm was 2100 times higher than that of isoprothiolane 12.81ppm. $LC_{50}$ values of acute toxicity of the chemicals to carp were endosulfan 0.0026ppm, captafol 0.062ppm, chlorothalonil 0.078ppm, captan 0.14ppm, and butachlor 0.47ppm, carbofuran 0.52ppm, nitrofen 0.58ppm, diazinon 0.81ppm, cartap 0.82ppm, methomyl 5.03ppm, propanil 10.67ppm, malathion 11.92ppm, and isoprothiolane 13.20ppm. The acute toxicity of endosulfan was 5,000 times higher than that of isoprothiolane. The toxicity of diazinon, carbofuran, cartap, endosulfan, and nitrofen to carp was approximately 2-6 times as high as that to israeli carp, but the toxicity of malathion, methomyl and captafol to israeli carp was slightly higher than that to carp. AchE activity was inhibited by 31% and 52% after 96hr’s exposure of israeli carp to diazinon and malathion respectively. GST activity in israeli carp was significantly induced by methomyl exposure for 96 hr.