nekton

The collection of marine and freshwater organisms that can swim freely and are generally independent of currents, ranging in size from microscopic organisms to whales.

Swimming organisms considered collectively and in contrast with those that float and those that live upon or in the bottom. See plankton, benthos.

The aggregate of actively swimming animals in a body of water ranging from microscopic organisms to whales.

A generic term for organisms in the ocean that are capable of swimming independently of currents.

the aggregate of actively swimming animals in a body of water ranging from microscopic organisms to whales