Overview: Disease caused by bacteria of the genus Streptococcus or Streptococcus-like bacteria, such as enterococci and lactococci, is referred to as streptococcosis. Among the bacteria that have been identified as causing streptococcosis in fish, Streptococcus iniae is perhaps the most significant due to its virulence across a broad range of hosts, global distribution, economic impact and zoonotic risk. 1,2