This chapter covers the rule of bacteriocins and predatory bacteria in Antimicrobial Resistance (AMR) of aquaculture and aquatic environments. A wide variety of bacteriocins have been obtained from bacteria (either Gram-negative or positive) described for their suggestive benefits and possible applications. Bacteriocins might be used separately or in combination against bacterial infections, targeting lowering the rate of antibiotic usage and the resulting AMR. This will require studying their types, classification, mode of action, resistance pathways, and immune responses. Immune response in the case of strains producing bacteriocins includes proteins and transporting mechanisms that differ between bacteriocins types. This chapter will broaden our knowledge about bacteriocins and predatory bacteria.