The aim of this study is to assess the response of a multimarker approach in common carp Cyprinus carpio sampled from three Tunisian dam lakes selected according to different environmental and ecological characteristics. Glutathione-S-transferase (GST) activity was analyzed in carp liver and used as a phase II detoxification enzyme, hepatic metallothionein content (MTs) was used as a metallic stress indicator, and cholinesterase activities were analyzed in muscle and brain and used as neurotoxicity biomarker. Micronucleus frequency test (MN) as a genotoxicity marker. GST and MT levels showed an increase in fish from the Bir Mcherga site and a decrease in Sidi Saâd site with respect to fish from Nebhana site. Results showed a strong inhibition of cholinesterase activities in fish from Bir Mcherga and Sidi Saâd sites compared to Nebhana site. Relatively high level of MN is reported specially in fish blood from the Bir Mcherga site.