The invention provides gene chips for detecting multiple pathogenic bacteria in animals cultivated in sea water and uses thereof. The pathogenic bacteria include: Vibrio anguillarum, Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, Vibrio vulnificus, Non-O1 Vibrio cholerae, Vibrio fluvialis, Vibrio fischeri, Vibrio splendidus, Vibrio mimicus, Vibrio salmonicida, Aeromonas hydrophila, Aeromonas sobria, Aeromonas salmonicida, Edwardsiella tarda, Edwardsiella ictaluri, Renibacterium salmoninarum, Mycobacterium marinum, Pseudomonas, and Streptococcus.