Plankton means “drifters” or “floaters.” Many people assume that all plankton are small, however the word does not refer to the size of an organism, but rather how they move around in the water. One example of a type of plankton that is not well known is a jelly (“jellyfish”, but they’re not really fish). These plankton can be as large as 6 ft and have tentacles over 100 ft long. Plankton, like these jellies, are still able to move in the water but have no control over where they go.
There are two main types of plankton, phytoplankton and zooplankton. Phytoplankton are plant plankton and are often much smaller than most zooplankton. Zooplankton are animal plankton and are usually larger than other phytoplankton. Depending on the species, Zooplankton either eat phytoplankton, or even other zooplankton. Many other creatures including juvenile fish rely on phytoplankton as a source of food. In fact, plankton as a whole, represent the base of the food chain in the ocean.