The word nekton means any group of living organisms in water that are able to move through the water, not just float. These can be as big as a pod of whales or as small as microscopic organisms.

Nekton are organisms that swim in the ocean and its movements are primarily controlled by currents, tides and waves. Examples of nekton are goldfish, tadpoles and turtles. You can find more information here: http://en.wikipedia.org/wiki/Nekton...