Fish Tilapia nilotica, Mormyrops anguilloides and Schilbe mystus, captured at port Socopla-Lomata on the Congo River in Mbandaka were analyzed by X-ray fluorescence spectrometer, brand Xepos III in accordance with the laboratory’s operating mode; to assess lead, cadmium and mercury contamination. The results showed concentrations higher than the edibility standards of the European Union and the concentrations observed in the water of the fishing site. The species Mormyrops anguilloides accumulates more cadmium while lead and mercury are more accumulated in Tilapia nilotica.