"In confined, heavily stocked, commercial systems, Vibrio disease outbreaks can proceed rapidly. Therefore, prevention is essential to any management scheme. As Vibrio species are believed to be opportunistic, conditions which favor a disease outbreak are often caused by environmental stress which can be avoided. Poor nutrition or water quality, improper handling, overcrowding, and the presence of other disease-causing agents will all increase your fish's chances of contracting a Vibrio infection. Parasites are of special concern, as they often cause damage to fish tissue, creating an ideal location for Vibrio infections to begin.
Chemical treatments, including the use of copper compounds, can be harsh on fish and have been reported to precipitate Vibrio disease outbreaks.
Quarantine of new fish and good sanitation practices should be used at all times, and will minimize the spread of Vibrio infection from infected to uninfected fish, should a disease outbreak occur. New fish should always be kept away from existing fish. Tanks and culture facilities should be kept clean and free of any unnecessary wastes.
Treatment
Before any treatment with antibiotics, a thorough investigation of water quality and husbandry practices should be conducted. Removal of underlying problems is essential to successful resolution of the problem. Occasionally, removal of contributing factors (i.e., poor water quality) will be all that is required to control the infection, but in most cases it is prudent to treat an active Vibrio outbreak with antibiotic therapy." (taken from
http://edis.ifas.ufl.edu/FA036)