Recently, fish parasites have been used as a biomonitoring tool to indicate the health status of ecosystems. Therefore, this research aimed to evaluate the potential capacity of Contracaecum quadripapillatum larvae as accumulation indicators for metal pollution and compare metal concentrations in host tissues of non-infected and infected fish: Lates niloticus from the Nile River. Accumulations of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in larval nematodes and tissues of the liver, kidney, and muscles of both infected and non-infected fish were determined. All metal concentrations exhibit a significantly higher increase in larval nematodes than the muscles of infected fish and vice versa except Cd in the kidney. On the other hand, only Cd, Mn, Pb, and Zn concentrations were significantly higher in the parasite than in the host liver. Therefore, bioaccumulation factors were most obvious and effective in the muscles of infected