Abstract
Aeromonas salmonicida was isolated from diseased yamame (Oncorhynchus masou) at 15, 20, and 25°C. Ten colonies were taken from each of ten isolates and were subcultured at the corresponding temperatures. Colonies incubated at 15 and 20°C showed strong auto-agglutination but 40% of colonies incubated at 25°C didn't clearly show auto-agglutination. It was also observed that strains isolated from diseased iwana (Salvelinus leucomaenis) at 20°C and subcultured at 25°C showed weak or no agglutination. These observations strongly suggested that A. salmonicida should be isolated and subcultured at 15°C or 20°C in order to retain their auto-agglutinability.
