Bacteriophages for aquaculture: Are they beneficial or inimical

World fisheries production is projected at 164 million tonnes in 2020, and a major increase in the quantity of fish produced is expected to originate from aquaculture. Diseases represent a severe threat to aquaculture productivity and natural/organic strategies to combat infectious diseases are gaining new ground to address the issues of antibiotic resistance of bacteria and issues related to antibiotic residues in aquatic food animals. Phage therapy is currently considered as a viable alternative to antibiotics for treatment of bacterial infections in aquaculture systems. A cocktail of lytic phages and a synergistic combination of phages and other antimicrobials are viable options to control bacterial infections and at the same time evade phage resistance. However, lysogenic phages have the ability to transform non-virulent bacterial strains in to virulent strains which may cripple aquatic food production and also threaten food safety. The review focuses on the roles of bacteriophages and their implications for aquatic food production and food safety.