Plankton is a copepod , which is a tiny marine crustacean, and more broadly a type of zooplankton.

Quick Scoop

  • In SpongeBob SquarePants , Sheldon J. Plankton is usually described as a planktonic copepod.
  • Real plankton is not one single animal; it’s a group of tiny drifting organisms, and Plankton fits the zooplankton side of that group.
  • So the simplest answer is: he’s a small crustacean , not a fish or insect.

Tiny detail

The name is a little confusing on purpose. In real life, “plankton” is an umbrella term, while the character “Plankton” is specifically portrayed as a copepod.

TL;DR: Plankton from SpongeBob is a copepod, which is a type of zooplankton.