Pasteurella piscicida is the aetiological agent of pasteurellosis or pseudotuberculosis, one of the most threatening diseases of wild and cultured marine fish. This bacterium has been reported from many geographical areas including USA, Japan, and the Mediterranean countries. In this review, the biochemical, serological, and molecular characteristics of the pathogen are described. In addition, its main virulence mechanisms, such as the presence of capsule, the iron uptake system, and the phospholipase activity, as well as their putative role in the pathogenicity of P. piscicida are also discussed. Finally, a detailed survey of the strategies for controlling the disease is performed, with a special emphasis on the vaccination programmes and the most effective protective antigens to be included in the vaccine formulations.