The present study is undertaken to investigate the biochemical composition in cichlid fish, Oreochromis mossambicus, in two lentic water bodies of Tumkur district, Karnataka, during May 2022 to April 2023. Glucose, glycogen, total proteins, total lipids, and free amino acids were estimated. In tank 1, the glucose content varied from 2.09 µmol/mg in gills and 21.04 µmol/mg in liver. However, glycogen level deviated between 2.32 µmol/mg in gills and 11.21 µmol/mg in liver. While, total protein content varied from 4.11 µmol/mg in gills and 49.01 µmol/mg in muscles. Total lipid content varied from 23.09 µmol/mg in liver and 130.52 µmol/mg in muscle. Nevertheless, free amino acids deviated from 1.59 µmol/mg in kidney and 39.00 µmol/mg in liver. In tank 2, glucose content varied from 3.51 µmol/mg in gills and 15.60 µmol/mg in muscles. Glycogen level was highest in liver 9.98 µmol/mg and lowest in the kidney with 3.01 µmol/mg. Total protein level fluctuated from 5.05 µmol/mg in gills and 48.01 µmol/mg in muscle tissue. The total lipids were minimum in the kidney with 38.05 µmol/mg and maximum in muscles with 76.80 µmol/mg... Free amino acids content was lowest in the kidney with 1.99 µmol/mg and maximum in the muscles with 30.15 µmol/mg. The investigation showed that the chemical composition is not the same in all tissues and months. It was also observed that the biochemical composition of fish depends mostly on size, maturity, gender as well as breeding season. Total proteins and total lipids were highest in muscle tissue. Glucose content was lower in the Gills, but Glycogen was minimal in the Gills and the Kidney. However, free amino acids were lower in the kidney. The reduction of Protein, Glycogen, and lipid contents may be due to the utilization towards the maturation of the gonads.