Effects of twenty-five compounds on four species of aquatic fungi (Saprolegniales) pathogenic to fish

Four species of aquatic fungi (Achlya flagellata, A. racemosa, Saprolegnia hypogyna, and S. megasperma) were exposed to 25 chemicals representing seven classes of compounds for 15 and 60 min, in an effort to identify potential fungicidal agents for use in fish culture. The antifungal activity of each chemical was compared with that of malachite green, a reference compound with known fungicidal properties but not registered for fishery use. Six compounds which inhibited fungal growth on artificial media at concentrations of < 100 mg/l (listed in order of decreasing antifungal activity) were the cationics Du-ter^® and copper oxychloride sulfate, the amine Lesan^®, the amide BAS-389-O1F and the cationics Cuprimyxin^® and Roccal^® II. Certain chemicals from these classes of compounds may have promise as aquatic fungicides.