
Sodium (Na+), potassium (K+) and Chloride (Cl¯) play an important role in osmoregulation and homeostasis. In the present study sodium, potassium, chloride and phosphate concentration in the blood of four Indian fresh water carps, Labeo rohita, Catla catla, Cirrhana mrigala and Labeo fimbriatus has been investigated in relation to a aquatic body. The results indicate that higher concentration of sodium in the blood of all the four types of carps has been noticed in comparison to other electrolytes. The degree of these concentration is as sodium>chloride>phosphate>potassium. The aquatic body in which these fishes are harbored has water with proper electrolyte concentration needed for physiological activities including osmoregulation and homeostatic mechanisms. Hence, the results of blood electrolytes found in these fishes are in normal levels indicating proper environmental conditions for their survival and are in healthy.