Amyloodinium ocellatum, also known as marine velvet, is a species of microbial parasitic dinoflagellates of the Amyloodinium genus. Currently, A. ocellatum has been the only species discovered in the Amyloodinium genus and has been found in various aquatic regions around the world in both tropical and temperate habitats. A. ocellatum is a temperature dependent microbe which can live in both salt and freshwater. A. ocellatum is also an obligate parasitic microbe, depending on marine animals to survive and complete their life cycles. The life cycle of A. ocellatum follows a parasitic growth model, maturing from a trophont to a tomont, before growing into a dinospore. First analyzed in the 1930s, A. ocellatum has since been identified as a major agent of disease among marine life.