Five species of freshwater fish and nine marine fishes were studied to determine the presence of Aeromonas hydrophila, an etiological agent in fish disease. This was done with the API 20E System (Analytab Products, Plainview, N.Y.) the standardized miniaturized version of conventional procedures for identifying Enterobacteriaceae and other gram-negative bacteria. This is a ready-to-use microtube system designed to perform 23 standard biochemical tests from isolated colonies of bacteria on plating medium.
All the five freshwater fishers and two of the nine marine fishes were found positive for Aeromonas hydrophila.