Inhibition of spore growth of aquatic fungi in genus Achlya was studied by bathing spores in either sodium chloride or acetic acid with various concentrations for 30 and 60 minutes before counted on Glucose Yeast Extract Agar. The minimum inhibitory concentrations (MIC) of either sodium chloride or acetic acid that can inhibit fungi spores were 1.25 percent and 0.02 percent, respectively and hatch rates of Mekong Giant Catfish eggs obtained from artificial insemination were 4.43 and 11.10 percent, respectively at 12.23 percent of control group. To inhibit the infection of Achlya sp. E.MCF 1-02 spores to Mekong Giant Catfish eggs, the eggs were bathed in 10**(4) spores/ml either 1.25 percent sodium chloride or 0.02 percent acetic acid for 30 minutes. The fries in sodium chloride tested group (0 percent) were lower than the negative and positive control (12.23 and 7.7 percent, respectively) while the fries in acetic acid tested group (25.9percent) were higher than the both of control groups.