In the present study histological effects of copper sulphate on, 180 common carp, Cyprinus carpio, fingerlings were studied. In this regard, fish of treatment groups were exposed to 2, 4, 6, 8 and 10 ppm of copper sulphate during 4 days. Behaviours and clinical signs of fish were recorded during the experiment, and samples were done from kidney, liver and gill of moribund and fresh dead fish, a...