Technical Abstract: Streptococcal disease results in severe losses of fish in intensive culture operations throughout the world, including tilapia and hybrid striped bass in the United States. The organisms responsible are Gram-positive cocci, particularly Streptococcus sp. and Enterococcus sp. These microorganisms are facultative anaerobes (i.e., can grow in the absence of oxygen). This characteristic allows one to presumptively identify these groups (i.e., catalase negative). Recently, much attention has been focused on Streptococcus iniae in North America because of the reported potential for human infection resulting from handling live fish. This publicity resulted from recent cases of S. iniae infection in a single non-US location. Prevention of streptococcal disease may be possible by vaccination of fish. However, at present no commercially licensed vaccines are available. Currently, the best form of control for streptococcal disease is management (i.e., rapid removal of the source of infection or dead and dying fish, water quality management, nutrition and feeding management and breeding of more disease resistant stocks).