Aeromonas Infections
Ruth Francis-Floyd Back to Page 1

Motile Aeromonas Septicemia (MAS) is a common bacterial disease, caused by Aeromonas, which affects warmwater fish, both in commercial production systems and in natural waters. Frequently, MAS outbreaks are stress-related and elimination of the underlying stress factor may be sufficient to resolve the disease outbreak. It is important to run antibiotic sensitivity tests prior to using antibiotics for controlling Aeromonas outbreaks. Many strains of Aeromonas are resistant to commonly-used antibiotics, and it is important to determine which drug should be used before spending time and money on an ineffective product.

Anytime an Aeromonas infection persists as a chronic problem, it is important to make an effort to determine if an underlying stress factor is causing the fish to have insufficient immune protection from the bacteria. Evaluate the water quality, nutrition, handling, and use of drugs and chemicals. Deficiencies in any of these areas could predispose fish to Aeromonas infections. Cleanliness and good management practices will reduce Aeromonas outbreaks in a fish production unit.


1. This document is FA-14, one of a series of the Department of Large Animal Clinical Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Date first printed, June 1991. Please visit the FAIRS Website at

2. Ruth Francis-Floyd, IFAS Extension Veterinarian, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.


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Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / Christine Taylor Waddill, Dean


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