Abstract: The effects of probiotics I containing primarily Bacillus subtilis and probiotics II containing a mixture of various microorganisms on weight gain,food conversion ratio and drug cost of common carp（Cyprinus carpio）,Crucian carp（Carassius auratus） and grass carp（Ctenophyargodon idellus） in culture ponds in Heilongjiang and Liaoning provinces.The probiotics,alone or together,were showed to have influence on weight gain,the food conversion ratio and the drug cost in the fish culture.There were 423.57% higher weight gain in Heilongjiang province and 90% higher weight gain in Liaoning province in the ponds treated with the probiotics used together,than that in the control ponds with lower drug production cost of 29% in Heilongjiang province and 56.25% in Liaoning province.The food conversion ratio was found to be decreased by 0.35 and 0.05 in the ponds treated with probiotics used together,indicating that the probiotics have important influence on the profit of grass carp culture in Liaoning province and of common carp farming in Heilongjiang and have a promotion of green aquaculture with less drugs,less feed and more profits.

Key words: probiotics, fish culture in ponds, Heiolongjiang province, Liaoning province, profit