This chapter describes the clear and intensifying link between cyanobacteria and aquaculture. Cyanobacteria are photosynthetic bacteria that were once thought to be a type of alga. The chapter explores the link between cyanobacteria and aquaculture, and examines the Scientific understanding in this multidisciplinary eld and provides an assessment of the level of risk posed by cyanobacterial toxins to seafood as well as considers possible future directions for research. Many species are capable of producing secondary metabolites by nonribosomal processes that include cyanobacterial toxins or cyanotoxins. The naming of microcystins reflects the fact that the toxin was first discovered in members of the genera Microcystis, but they have since been found in many genera of cyanobacteria. The most toxic forms of saxitoxins are the carbamate moieties and they include saxitoxin, neosaxitoxin, and gonyautoxins. Toxic microalgal blooms are the most common source of the toxins; there is growing evidence that saxitoxins are produced by freshwater and brackish water cyanobacteria.