Deep sea
The dark water below 200 metres, down to the trenches. 42 fish on EveryFish so far.
Below 200 metres sunlight fades, and below about 1,000 metres it is completely dark. The deep sea is cold, under huge pressure and short of food, yet it is the largest living space on Earth and full of fish. In the twilight zone, lanternfish and bristlemouths gather in vast numbers. Deeper down live anglerfish, gulper eels, grenadiers and snailfish, the deepest fish known.
Ways to live in the dark
Many deep-sea fish make their own light, using it as lures, to signal or to hide their outline from below. Big mouths, stretchy stomachs and long teeth help them catch scarce prey. Many have weak muscles and watery bodies to save energy. Some rise towards the surface at night to feed, a daily journey called vertical migration. A snailfish was filmed at 8,336 metres in a trench off Japan in 2022, close to the limit at which fish are thought able to live.
Slow lives and new threats
Deep-sea fish often grow slowly and live long. The orange roughy may live well over a century, and it was heavily fished from the 1980s off New Zealand and Australia before stocks fell. Bottom trawling on seamounts can destroy cold-water corals that took thousands of years to grow. Proposals to mine the deep sea floor for metals are debated: supporters cite the need for battery metals, while scientists warn of damage to little-known habitats.
Famous deep sea fish
Still to be written: Orange roughy, Goblin shark, Frilled shark.
Further reading
WorldViperfish
Deep-sea fish with fang-like teeth and bioluminescent lures in the genus Chauliodus.Other · Open ocean · 1801
WorldMarine hatchetfish
Small deep-sea fish with a distinctive compressed body shape and bioluminescent camouflage.Other · Open ocean
WorldMariana snailfish
A deep-sea fish from the Mariana Trench with transparent skin and large eggs.Other · Deep sea · 2017
WorldSabertooth fish
Small deep-sea aulopiforms with large recurved teeth and tubular eyes.Other · Deep sea
WorldAtlantic footballfish
Deep-sea anglerfish with a glowing lureOther · Open ocean · 1837
WorldCrestfish
Deep-sea ribbon fish with a head crest and ink sacsOther · Open ocean
WorldBarreleye
Deep-sea fish with tubular eyes and a light-producing anusOther · Open ocean
WorldBristlemouths
A family of abundant deep-sea fish with bioluminescent organs and bristle-like teeth.Other · Open ocean
WorldAnglerfish
Ray-finned fish using a modified dorsal fin ray as a lure to catch prey.Other · Coasts and shelves · 1829
WorldGrenadiers
Deep-sea gadiform fish with slender bodies and long tails, found globally in ocean depths.Other · Deep sea · 1765
WorldSloane's viperfish
Deep-sea dragonfish with huge teeth and light organsOther · Open ocean · 1801
WorldBlack dragonfish
Deep-sea fish with infrared light and stalked larval eyesOther · Open ocean
WorldBarreleye
Deep-sea argentiniform fish with transparent heads and tubular eyes.Other · Deep sea
🇦🇺 Australia and 1 moreBlobfish
A gelatinous deep-sea fish from Australia and New Zealand waters.Other · Deep sea
WorldBlack swallower
Deep-sea fish that eats prey larger than itselfOther · Open ocean
WorldPacific blackdragon
Deep-sea fish with light-absorbing skin and a glowing chin lure.Other · Open ocean
WorldTripod fish
Deep-sea fish that stands on elongated finsOther · Open ocean
Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Common fangtooth: Brian Suda, CC BY-SA 2.0, source
- Viperfish: NOAA Ocean Exploration, Voyage to the Ridge 2022, Public domain, source
- Marine hatchetfish: Unknown author, CC BY-SA 3.0, source
- Atlantic footballfish: Unknown author, CC BY-SA 2.5, source
- Snailfish: Erin McKittrick, CC BY 4.0, source
- Telescopefish: Unknown author, Public domain, source
- Deepsea lizardfish: Bideault, Public domain, source
- Ribbonfish: Personnel of NOAA Ship DELAWARE II, Public domain, source
- Glasshead barreleye: Adrian Flynn, CC BY 1.0, source
- Stareater: Peter Marriott, Public domain, source
- Crestfish: Unknown author, Public domain, source
- Barreleye: S. Johnsen (Duke Uni.) for courtesy of photos, J. Hlidberg for courtes, CC BY 4.0, source
- Bristlemouths: Unknown author, Public domain, source
- Lanternfish: Emma Kissling, Public domain, source
- Anglerfish: Unknown author, Public domain, source
- Oarfish: Sandstein, CC BY 3.0, source
- Grenadiers: Unknown author, Public domain, source
- Humpback anglerfish: Emőke Dénes, CC BY-SA 4.0, source
- Pelican eel: Unknown author, Public domain, source
- Triplewart seadevil: Dr Tony Ayling, CC BY-SA 1.0, source
- Sloane's viperfish: Gervais et Boulart, Public domain, source
- Black dragonfish: GM. Woodward, Public domain, source
- Barreleye: Unknown author, Public domain, source
- Blobfish: Alan Riverstone McCulloch (1885-1925), Public domain, source
- Black swallower: Unknown author, Public domain, source
- Pacific blackdragon: Unknown author, Public domain, source
- Roundnose grenadier: Carl Nielsen, Public domain, source
- Tripod fish: null, CC BY 4.0, source
- Giant grenadier: Joe Mabel, CC BY-SA 4.0, source
