Aeromonad Infection

(Aeromonas Septicemia)

Common Indicators: Red marks on body, skin ulcers, sluggishness, swollen abdomen.

Various forms of the Aeromonis bacteria are responsible for a variety of illnesses in fish. The Aeromonis hydrophila bacteria, for example, is one of the possible culprits in fin rot. An Aeromonad (Aeromonis salmonicida) is also linked to goldfish and koi ulcer diseases as it attacks salmonids (fish related to salmon, as is the case with koi and goldfish).

For most freshwater aquarists not keeping goldfish or koi, Aeromonis septicemia infections (sometimes called Red-Sore Disease) is the most likely contact with Aeromonads. This bacteria attacks a wide variety of freshwater fish. According to Edward J. Noga, Ph.D. in his work on the subject, Risk factors include overcrowding, polluted aquarium water and overly warm water temperature. Free-swimming Aeromonis bacteria are, according to this, “relatively weak pathogens”, but it’s acknowledged that poor water conditions, stress due to overcrowding, etc. provide an opportunity to these bacteria, as polluted water both provides a rich nutrient culture for them and induces stress on the fish, reducing their resistance.

Visible symptoms are skin ulcers or lesions, which often can become reddish or grey. Also, fluid build-up in the lower intestine and stomach creating a visible swollen abdomen. However, because there are variations in the various forms of “motile aeromonads”, there can be variations in these symptoms depending on the specific infecting organisms.

It is generally agreed that preventative steps such as maintaining good water quality, stable appropriate water temperatures and avoiding overcrowding and other stress factors for fish can help avoid this disorder. Also, in the U.S., there are antibiotics for fish available without a prescription. In other parts of the world, including the EU, it is necessary to be prescribed by a veterinarian. However, there are many strains that are antibiotic resistant (or have become so due to overuse of antibiotics).


Bibliography & Further Reading:

Noga, Edward J. “Fish Disease Diagnosis and Treatment.” 2nd Ed. John Wiley & Sons; 2010

Stoskopf, Michael K. “Fish Medicine.” W.B. Saunders; 1993

Untergasser, Dieter Ed., “Handbook of Fish Diseases”. TFH Publications; 1989

Articles & Papers:

Purdue University., “Bacterial Pathogens of Fish”.

Petty, Barbara D. Ed. and Francis-Floyd, Ruth, Ed. “Bacterial Diseases of Fish.” The Merck Veterinary Manual; 2015

Advisory: The information contained in this article entry is for informational purposes only, and is not a substitute for consultation with a veterinary professional nor treatment under the supervision of a veterinary professional. New Life International does not guarantee the accuracy or completeness of the information nor of the sources cited as reference. This articles is not a diagnostic tool or reference, nor should be considered treatment advice by New Life International.

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