Consumption of fish and fish by products assures various health benefits, but on the other hand the fish processing wastes if not discarded properly pose a serious environment threat. Tilapias are commonly available cichlid fishes which are considered to possess various biological importance. The objective of the work is to analyze and compare the similarities and differences in the nutritional quality of the exotic fish Oreochromis mossambicus found in brackish water and fresh water environments. The estuary adapted tilapia and freshwater tilapia was collected and processed as head and bone flours. The samples were further analyzed and the results in 100 g of Estuarine Tilapia Head Flour (ETHF) was composed of moisture (5.87 ± 0.003%), protein (32.06 ± 0.02%) total lipids (0.202 ±0.003 %), carbohydrates (1.44 ± 0.005%) and ash (1.15 ± 0.006%). The results in 100 g of Estuarine Tilapia Bone Flour (ETBF) was found as moisture (4.20 ± 0.006%), protein (31.48 ± 0.07%), total lipids (0.217 ± 0.002), carbohydrates (0.13 ± 0.004%) and ash (0.89 ±0.004%). The proximate content in Freshwater Tilapia Head Flour (FTHF) ranged as moisture (5.79 ± 0.01%), protein (32.50 ± 0.02%), total lipids (0.202 ± 0.009%), carbohydrates (1.54 ± 0.02%) and ash (1.16 ± 0.003). The proximate content in Freshwater Tilapia Bone Flour (FTBF) ranged as moisture (5.77 ± 0.01%), protein (32.58 ± 0.03%), total lipids (0.200 ± 0.005%), carbohydrates (1.48 ± 0.02%) and ash (1.23 ± 0.01%). The fatty acid occurring in the highest proportions was alpha linolenic acid both ETHF (2.492±0.003mg) and ETBF (2.374±0.002mg). The fatty acid composition in FTHF occurring in the highest proportion was palmitic acid (0.983±0.002mg) and in FTBF the highest proportion was found in stearic acid (0.785±0.005mg). In the amino acid analysis, the highest values were recorded in phenyl alanine for ETHF (1.986±0.002%) and lysine in ETBF (1.364±0.003%). Phenyl alanine content was found higher in both FTHF (1.889±0.002%) and FTBF (1.981±0.003%). The essential vitamins and minerals were also analyzed and the results are discussed in detail.