The concentrations of seven heavy metals (Al, As, Cd, Cu, Fe, Pb and Zn) were detected in muscle tissues of Tilapia sp (black tilapia) collected from the lake of Taman Mutiara, Puchong. Samples were collected for several months in the end of 2009 at three sampling points. Heavy metals in fish and water samples were analyzed by Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). Only Al, Cu, Fe and Zn were detected in the order Fe > Zn > Al > Cu, whereas concentrations of As, Cd and Pb were below the detection limit. The concentrations of heavy metals in water samples were low and below the detection limit. The levels of heavy metals in the fish samples can be considered as a serious matter of concern as it may be consumed and it signifies the degradation of lake quality. Generally, the sources of heavy metals in the Tasik Mutiara, Puchong could be attributed to the illegal waste dumping activity and discharge from the nearby sewage treatment plant into the lake which promote eutrophication in the lake. It could also be attributed to the Low Dissolved Oxygen (DO) levels in the lake.