Due to high and increasing demand for fish protein, aquaculture is currently the fastest-growing food producing sector in the world. Since the 1970's, it has been growing at an average yearly rate of 8.9-9.1%. There are however some bottlenecks associated with production cycle in aquaculture, particularly occurrence of diseases. It is generally accepted that diseses are still a major constraint to sustainable aquaculture production. Cultured aquatic species are often exposed to stressful conditions, eventually becoming more susceptible to microbial infections. In order to protect these species, the common practice has long been to disinfect the water before use and to apply chemotheraphy. Yet, these practices are considered undesirable. In particular, the wide and discriminate use of chemotherapy has resulted in promoting selection and dissemination of antibiotic-resistant bacteria in both the target organisms, as well as in the environment and moreover to humans. Nowadays, clinical trials have shifted to testing marine natural products against macroalgae, sponges and sea cucumbers. Bioactive compounds derived from these species have shown promising leads for extended preclinical assessment.