author(s)
Sunita Rani, Rajender Kumar Gupta and Jyoti Yadav

abstract
The present study was conducted in 2012 to envisage the impact of heavy metals viz. cadmium (0.02, 0.04 and 0.06 ppm) and zinc (0.02, 0.04 and 0.06 ppm) alone and in combinations (Cd +Zn) at 0.02+0.02,0.04+0.04 and 0.06+0.06 ppm concentrations. The analysis of alteration in behavior, morphology and acetylcholinesterase activity was analyzed in three carps viz. Labeo rohita, Catla catla and Cirrhinus mrigala. Maximum reduction in enzyme activity upto 9.21%, 12.42% and 15.80% has been observed in C. catla, L. rohita and C. mrigala respectively, when treated with Cd (0.06 ppm). When the fishes were exposed to Zn (0.06 ppm), reduction upto 4.08%, 10.60% and 13.75% has been observed in C. catla, L. rohita and C. mrigala respectively. It may also be noted that the maximum inhibition (18.67%) of enzyme activity was observed in C. mrigala when it was exposed to Cd+Zn (0.06+0.06 ppm).