Fin Rot/Tail Rot

(A Flavobacterium columnare , Aeromonas hydrophila/liquefaciens, Pseudomonas  sp.,)

Common Indicators: Red marks on fins, decay of fin membrane, ragged or decaying  fins

Fin rot is a clinical-sign rather than a disease caused by a single specific organism, and the term covers disorders caused by a grouping of possible bacteria in freshwater fish, including commonly two varieties of Aeromonas bacteria (hydrophila and liquefaciens), as well as several varieties of Pseudomonas bacteria. Also cited is Flavobacterium columnare.

Bacteria such as Aeromonas hydrophila is actually ubiquitous in nature, and has been found in the gut of healthy fish. Thus, their presence doesn’t necessarily create a problem in tanks that have good water quality and healthy non-stressed fish with fully functional immune systems. It is generally recognized  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. Likewise it is generally agreed that under such conditions, damage to the skin or fins can provide vectors for infection.

In addition to decay of the fins, signs of infection by these organisms can manifest as (but not limited to):  swimming abnormalities, loss of appetite, pale gills, bloating, and ulcers surrounded by red inflamed tissue.

Beyond maintaining good aquarium environment conditions as a preventative, antibiotics are frequently used to treat fin rot. In the U.S., antibiotics like erythromycin are cephalexin are available without a prescription. In other parts of the world, including the EU, it is necessary to be prescribed by a veterinarian.


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

Articles & Papers:

Swann, LaDon and White, Randy M. “Diagnosis and Treatment of ‘Aeromonas hydrophila’ Infection of Fish.’; Purdue University Aquaculture Extension/Indiana Sea Grant Program; 1991

Monks, Neale. “Aquarium Fish Finrot: Identifying and reating aquarium fish finrot.” (Aquarium USA Magazine);

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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