Tropical fish medicine. Bacterial culture and evaluation of diseases of fish.

Bacteria are ubiquitous in nature. Fish are constantly exposed to bacteria, and usually only succumb to an infection after having been exposed to prolonged periods of stress. Before making a diagnosis of a bacterial disease, it is necessary to eliminate the possibility of environmental or parasitic problems. Environmental factors may act as stressors and can predispose a fish to bacterial disease while affecting the fish simultaneously. Clinical signs caused by the various bacterial pathogens are very similar. Therefore, to make a definitive bacterial diagnosis, it is necessary to culture and identify the organisms involved.