Key components of invertebrate, such as protozoa, metazoa, mollusca, arthropoda, echinodermata will be introduced in the class. Some important species in aquaculture industry will be emphasized and given as examples in the class. All examples, including aquatic sea urchin, crab, lobster, squid, prawn, grass crab, and so on, will be discussed on their biology, distribution, ecology and life history for aquaculture.