The aim of the present study was to obtain a baseline data on the blood cell size, morphology, differential leucocyte count, haematological parameters of and biochemical parameters in Catla catla since there is a limited information in the published literature. Blood samples were collected from the caudal vein of apparently healthy fish (male: n=15 and female: n=15) were collected. Haematological and biochemical values of the blood samples were determined using standard techniques. The morphological features of blood cells were described according to observations made by light microscopy. The various types of blood cells measurement were carried out with the help of Microscope Eyepiece Digital Camera and computer. From microscopic observation blood cells such as erythrocytes, five types of leucocytes: lymphocytes, monocytes, heterophils, neutrophil and eosinophils, were distinguished and characterised. Statistical analysis revealed haemoglobin, PCV (p<0.001), lymphocytes , heterophils (p<0.05) and cell morphometry except heterophil in Catla catla were significantly influenced by sex.
