Studies of some biochemical changes in the tissues of Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton) exposed to NH3-N, NO2-N and NO3-N.

Biochemical changes, total proteins, glycogen, aspartate and alanine (AAT and ALAT) amino transferases were studied with exposure of sublethal concentrations of NH3-N, NO2-N and NO3-N to the freshwater fish Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton). Depletion in the food reserves and enzyme activity was observed in all the three fish species exposed to these toxicants. Hence, the concentrations of NH3, NO2 and NO3 in water need to be monitored in water quality in aquaculture practices.