Fish acts as a good bioindicator for metal contamination. The contaminated metal ions are bonded into the protein biologically. The doping concentration and its properties were analyzed by the tools of electrical conductivity. For the analysis of fish species, Clarius batrachus was selected, subjected to metal-dissolved solution and studied for its muscle conductivity in both raw and pelletised forms. The various parameters analyzed were electrical conductivity and temperature dependent electrical conductivity on fish muscle protein in its unpelletised (natural) and pelletised form, when metals like copper, cadmium and lead were doped to the muscle protein. The studies carried out were atomic absorption spectroscopy (AAS), thermo gravimetric analysis (TGA) and electron paramagnetic resonance (EPR). The results showed that conductivity in muscle as well as its pelletised temperature dependent conductivity is a very good mechanism for the identification of cadmium, lead and copper contamination level. (C) 2008 Elsevier Ltd. All rights reserved.