Abstract: The different concentrations of Methylene Blue,Formaldehyde,Potassium Permanganate（KMnO4）,Sodium Chloride（NaCl）,and Malachite Green solution were used to control the impact of Saprolegniasis on eggs of Songpu mirror carp at water temperature of 24±1℃.The results showed that Methylene Blue solution（1100.00mg/L,10 min） and Formaldehyde solution（6000.00mg/L,10min） had a stronger inhibitory effect on Saprolegniasis and no significant influence on hatching rate.After the eggs was immersed in Methylene Blue solution for 10 min,the effective time lasted for 29.97 h,and abnormal rate of fries were found the lowest（only 1.55%）,while KMnO4 and NaCl solution did not show on significant inhibitory effects on the Saprolegniasis.In this experiment,we can draw a conclusion that,instead of Malachite Green solution,Methylene Blue solution can be used to prevent or control the Saprolegniasis.

Key words: Songpu mirror carp, fish egg, Saprolegniasis, methylene blue