Pelagic

From Microcosm Aquarium Explorer

Pelagic adjective

Pertaining to or found in the open sea or drifting on or near the surface; swimming, floating, or suspended in open water.

Pelagic-spawning marine fishes, for example, shed fertile, bouyant eggs that drift with the currents and hatch to yield pelagic larvae.

Pelagic is the opposite of benthic, which indicates bottom-dwelling or substrate-attached organisms. Benthic spawners lay their eggs on hard substrate or in the sand.