Plankton what are they?
Plankton are mostly tiny animal and plant organisms that float or weakly swim in the ocean's surface waters. Some plankton are single-celled while others are multi-celled---with some forming colonies. The word plankton comes from the Greek planktos, meaning drifting or wandering.
The organisms that make up plankton are very numerous and diverse; they can be grouped in many different ways. One division is based on the ability for photosynthesis; those plankton (mostly algae) that are capable of this process are called phytoplankton. Non-photosynthesizing (often termed animal) plankton are called zooplankton. The divisions of plankton are not made based on plant or animal characteristics---because some plankton can exhibit traits of both plants and animals.
Yes and no. typically plankton applies to microorganisms that are not fish. They are small microscopic animals. But more properly, plankton means drifter or floater. Anything that floats can be called a plankton. For example, the Porteguese Man of War is a plankton, while a copepod and diatom is also an aexample of plankton. Some plant are considered to be plankton and some algae are forms of phytoplankton.