Aquaculture is one the most proliferative agriculture industry owing to the increasing demand for fish products and decreasing wild catch. However, with intensive aquaculture, where stocks are kept in high density, microbial diseases would often emerge and result in outbreaks leading to massive deaths. In the past antibiotics are used to treat the infections. But, due to its misuse, resistant microbes have emerged and are now rampant in killing stocks. As a result, vaccines are very much preferr...