Cochlodinium polykrikoides

Cochlodinium polykrikoides (or Margalefidinium polykrikoides) is a species of red tide producing marine dinoflagellates known for causing fish kills around the world, and well known for fish kills in marine waters of Southeast Asia. C. polykrikoides has a wide geographic range, including North America, Central America, Western India, Southwestern Europe and Eastern Asia. Single cells of this species are ovoidal in shape, 30-50μm in length and 25-30μm in width.

Cochlodinium polykrikoides is a highly motile organism. They are generally found in aggregations of 4 or 8 cell zooids. Chain length is known to be affected by the presence of grazers and the inclusion of vitamins B1, B7 and B12. This species is also capable of mixotrophy, which makes them extremely persistent during a large algal bloom. C. polykrikoides exhibits diel vertical migration.