The present study was aimed to analyse the biochemical composition emphasise on Amino acids, protein with good amino acid content and minerals of Tank Goby Glossogobius giuris, native to fresh water to brackish water (Euryhaline). It is an unexploited fish commonly found in brackish water especially rich in Vembanad Lake, Kerala, India. Proximate composition of fish includes moisture 80.52%, protein 14.81%, Fat 2.82%, and Ash 1.08% respectively. Amino acids in the fish are divided in to three Essential, Conditionally essential and Non-Essential Amino acids. Among the essential amino acids Histidine (His) 1745.4 mg/100g was the most abundant. Isoleucine (Ile) and Leucine (Leu) had the lowest essential amino acid. Conditionally essential amino acids showed high percentage of Cysteine (18.54%) followed by Glycine (Gly) 5.9%. Alanine (2045.5 mg/100g) was found most significant concentration amongst the Non-essential amino acids. Significant amount of mineral, Phosphorous (402 mg/100g), Potassium (356.1 mg/100g), Calcium (340.8 mg/100g), Sodium (73.2 mg/100g) and Iron (1.5 mg/100g) reported in Tank goby. The heavy metals illustrated were Copper (0.033 ppm), Manganese (5.3 ppm), Zinc (17.21 ppm), Magnesium (154.1 ppm), Mercury (0.0035 ppm) and Chromium (15.8 ppm) respectively. The knowledge about the biochemical composition of the fish enhances the utility of the fish as good source of quality protein and amino acids.