Abstract: A study has been planned to investigate the effect of oil pollution with respect to heavy metals in edible herbivorous fishes. Toxic metal like Pb, Hg, As, Cd and Cr were analyzed by Atomic absorption spectrophotometry and subsequently related with nematode parasite. The food contents found in guts of fishes belong to coastal area consists of Phyto Plankton, mud, sand, dinoflagllates and molluscs. Results indicated that due to high percentages of heavy metals and nematode parasite, fishes get infected and experienced more rapid death. These fishes commonly supplied to Karachi city and may be toxic to human health. It was observed that nematode parasites were persistents in presence of toxic metals and they were attached to flesh of fish. Presence of nematode parasite and toxic metals in fishes may be related with the pollution caused by the spreading of oil from Tasman Sprit at Clifton beach Karachi.