Heavy metals pose a significant environmental threat to aquatic ecosystems, particularly in hypersaline lakes like Lake Qarun. These metals accumulate in aquatic organisms, including fish, disrupting biochemical and physiological functions. Solea aegyptiaca, an economically significant species, serves as a sentinel organism for assessing pollution impacts due to its ecological relevance. This study investigated the biochemical responses, antioxidant activity, and protein profile alterations in Solea aegyptiaca exposed to heavy metal contamination in Lake Qarun. Metal concentrations (Fe, Cu, Zn, Cd, Pb, and Ni) were analyzed in gills, liver, kidney, muscles, and skin of fish collected from various locations across the lake. Results showed significantly higher metal levels in fish from the eastern and southern regions compared to the northern and western regions (P< 0.05). Essential metals such as Zn, Fe, and Ni exceeded permissible thresholds for human consumption in muscle tissues, especially in the eastern and southern zones, while Cd and Pb remained below the acceptable limits. Biochemical assays revealed elevated glucose, AST, ALT, ALP, creatinine, and uric acid levels in fish from polluted regions, whereas unpolluted areas exhibited higher total protein, albumin, and hemoglobin levels. Antioxidant activity varied, with decreased SOD, GST, and GSH levels but increased CAT activity in polluted regions. Protein profiling showed the emergence and absence of specific molecular weight bands in gills, liver, and muscles, reflecting heavy metal stress. These findings demonstrate the significant physiological and biochemical impacts of heavy metals and underscore the potential of these biomarkers for environmental monitoring in aquatic ecosystems.