The haematological and serum biochemical studies has been carried out in two types of fresh water fishes collected from different habitat. The fresh water fish, Notopterus notopterus collected from a river and Channa marulius collected from a pond. The fish, N.notopterus is a continuously moving fish and frequently comes to the surface for gulping air and also respires through gills. The fish, Channa marulius remains in the bottom of pond and spends more time, very occasionally comes to the surface for gulping air. The haematological and serum biochemical parameters determined in these two fishes exhibited marked difference. All the parameters observed were on the higher side in the fish Channa marulius compared to that of the fish, N.notopterus. Indicating that behavioural pattern and habitat influence the blood parameters in fish