Technical Abstract: This invited article provides a comparison between fish and shrimp immunity, and reviews the use of immunostimulation, vaccination strategies and bacteriophage therapies. Immunostimulants, a heterogenous group of compounds that are derived from bacterial, plant and animal extracts are compounds believed to be capable of producing or aiding in the stimulation of immune responses. However, properly designed field trials and data analysis are often inadequate regarding the numbers of fish, treated replicates, untreated controls and known cause of mortality to be accurately interpreted. The risk/economic benefit factors are often unknown. Furthermore, does an immuostimulant provide long lasting protection in both juveniles and adult fish? More research is needed to demonstrate immunstimulant protection and economic benefit to fish farmer to completely accept their role in promoting fish health. Vaccination strategies increase survival as well as providing additional profits to the fish farmer by increased growth of healthy fish. Vaccinology is a valid, environmentally sound approach to producing specific immune responses that can be effective in the prevention of diseases in farmed fish. The use of safer alterative strategies such as vaccines and phage treatments represent progress towards solving, health issues and environmental problems cause by the use of antibiotics in aquaculture.