Abstract: The eggs and fries from grass carps and common carps were treated with different concentrations chromium in water body.It was found that toxic effects was caused at the concentration of more than 2mg/L groups treated with Cr.The fries lethal rate of 10 mg Cr/L groups reached to 30% during 168h.The eggs hatching rate of grass carps and common carps descended 46% and 88.9% respectively.The fries lethal rate of grass carps in 15 mg Cr/L group was 100% and the eggs hatching rate was zero.The endurance to chromium of two kinds of fish has no significantly.

Key words: chromium, grass, carps, common carps, embryros, fries, toxicity