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SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliamentSpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliament
EveryFish

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

Humpback anglerfishHunts with a glowing lureLanternfishAmong the most numerous fish in the seaGiant oarfishThe longest bony fish, rarely seen alivePelican eelA gulper with a huge mouth Mariana snailfishMariana snailfishThe Mariana snailfish of the trenches

Still to be written: Orange roughy, Goblin shark, Frilled shark.

Further reading

GroupSharkRayCarpCatfishSalmonidHerringCodTunaPerch-likeCichlidReef fishEelFlatfishLivebearerAncientOther
UseFood fishFarmedAquarium fishSport fishingCulture and faithVenomous or dangerousInvasiveScience and research
OrderBest knownA to ZOldest firstNewest firstBy size
WorldAnglerfish Ray-finned fish using a modified dorsal fin ray as a lure to catch prey.Other · Coasts and shelves · 1829 WorldOarfish Extremely long pelagic fish known for their ribbon-like bodies and association with sea serpent myths.Other · Open ocean · 1772 WorldRoundnose grenadier A large deep-sea fish from the northern Atlantic Ocean with a rounded head and long tail.Other · Deep sea 🇯🇵 Japan and 1 moreGiant grenadier A large deep-sea rattail from the North Pacific.Other · Open ocean

Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.

The weekly digest

Every Monday: the fish of the day, new pages on EveryFish, and the conferences and anniversaries of the week ahead.