Mollusks are the most successfully cultured and commercially important types of Shellfish. Shellfish are marine species consumed widely in the country. The major species exported to the European Union (EU) from Thailand are baby clams and green mussels. Green mussel culture in Thailand has a good potential for development from both biological and economical points of view. New culture methods such as the hanging method that has proven to be the most efficient in Europe should be investigated for their biological and economic feasibility. The importation of bivalve mollusks, echinoderms, tunicates, and marine gastropods is furthermore subject to EU Decision 97/275, which indicates the approved treatments to inhibit the development of pathogenic microbes in bivalve mollusks and marine gastropods. Red tide is a common name for a phenomenon also known as an algalbloom, an event in which estuarine, marine, or fresh water algae accumulate rapidly in the water column and result in discoloration of the surface water.