FaunaHub

Ocean fauna by depth

Ocean fauna by depth zone

The ocean is layered by depth, light, and pressure. Explore each zone — from the sunlit surface to the deepest trenches — with source-backed zone science and the marine animals documented in each layer.

How the ocean is layered

Most of the ocean's open water is divided into depth zones, defined mainly by how much sunlight reaches each layer. Light fades quickly with depth: photosynthesis is possible only near the surface, and below a few hundred metres the ocean is in permanent darkness, cold, and under increasing pressure.

These pages are educational. Animals are shown in the zone(s) they are documented to occur in — many move between layers — and the deep zones, which FaunaHub does not yet profile, are described from authoritative ocean-science sources.

Browse the depth zones

0–200 m
Sunlight ZoneEpipelagic zoneThe ocean's topmost layer, where enough sunlight reaches for photosynthesis. It holds most of the sea's plant-like life and the majority of familiar marine animals.18 featured profilesExplore
200–1,000 m
Twilight ZoneMesopelagic zoneBelow the sunlight zone, only faint blue light filters down and photosynthesis is no longer possible. Many animals rise toward the surface at night to feed.3 featured profilesExplore
1,000–4,000 m
Midnight ZoneBathypelagic zoneA realm of permanent darkness where food is scarce and pressure is immense. The animals here are highly specialised, and most are unfamiliar at the surface.Zone science overviewExplore
4,000–6,000 m
Abyssal ZoneAbyssopelagic zoneThe cold, dark expanse over much of the deep ocean floor — under enormous pressure, yet still inhabited by life adapted to the extreme.Zone science overviewExplore
6,000 m to the trench floor (~11,000 m)
Hadal ZoneHadopelagic zoneThe deepest part of the ocean — the great trenches. It endures the highest pressures on Earth, yet specially adapted animals still survive there.Zone science overviewExplore

Why depth shapes ocean life

Depth controls the basics of life in the sea. Light determines where plant-like life can grow; temperature and pressure shape what bodies can endure; and food becomes scarcer with depth, much of it drifting down from the productive surface as “marine snow.” These gradients explain why a sunlit reef and a deep trench hold such different animals.

Animals of the sunlit ocean

A selection of marine animals FaunaHub profiles that are documented in the sunlight zone.

Sources

Frequently Asked Questions

What are the ocean's depth zones?
Oceanographers divide the open ocean by depth into the sunlight (epipelagic, 0–200 m), twilight (mesopelagic, 200–1,000 m), midnight (bathypelagic, 1,000–4,000 m), abyssal (4,000–6,000 m), and hadal (6,000 m to the deepest trenches) zones, based mainly on how much light reaches each layer.
Why do most featured animals appear in the sunlight zone?
The sunlit surface holds most of the ocean's life and nearly all the animals FaunaHub currently profiles. The deeper zones are home to specialised deep-sea animals we do not yet profile; their pages describe that life from authoritative ocean-science sources.
Does a depth zone equal an animal's exact range?
No. Many animals move between zones — some migrate vertically every day. We show the zone(s) each animal is documented to occur in, with a confidence label, and never treat a zone as a complete range.