necto-, nect-, nekto-, nek- +

Characterized by having a foot, or feet, used for swimming.

The region of a siphonophore colony that bears nectophores (medusae specialized for propulsion).

An order of Hydrozoa (various simple and compound polyps and jellyfish) consisting of various free-swimming or floating pelagic mostly delicate transparent and often colored forms that are usually regarded as compound animals composed of zooids modified to perform various functions for the colony: such as, feeding, defense, and locomotion; which sometimes have two or more zooids in the form of a bell so that by their contractions they cause the colony to swim, and which often have a hollow float which keeps the colony afloat.

Those animals that inhabit the middle depths of the sea; neither benthos (animals and plants living on the bottom of a sea or lake) nor plankton (animal and plant life, mostly microscopic, which generally floats and drifts near the surface of a lake, river, or sea).

1. Organisms typically associated with the benthos that swim actively in the water column at certain periods.
2. Swimming off the sea bed or bottom.
3. Those forms of marine life that exist just above the ocean bottom and occasionally rest on it.

1. Animals of the pelagic zone of a sea, or lake, that are free-swimming and independent of tides, currents, and waves; such as, fish, whales, squid, crabs, and shrimps.
2. Nekton swim and are not simply carried passively by currents.

Nekton are limited in distribution by temperature and nutrient supplies, and they decrease with the increasing depth of the sea.

Uncounted myriads of little plants, together with the great numbers of tiny animals that feed on them, and on each other, form the plankton.

The term plankton is the name applied in 1887 by Victor Hensen, a German professor of zoology, with reference to the great company of marine creatures that drift at the mercy of the currents, as distinguished from the nekton, animals like fish and whales which are able to swim against the moving waters, and from the benthos, the plants and animals attached to the bottom of the sea or crawling on it.

There is no clear-cut dividing line between planktonic and nektonic creatures; some of the fish and other marine animals belong to the plankton during the early stages of their lives and then to the nekton later.

A reference to organisms that swim actively in open water, independent of water currents; as opposed to drifting.

Swimming on the back.