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Entry 245Filed under Breeding

What Fish Live at the Bottom of the Ocean?

Flatfish, eelpouts, grenadiers, cutthroat eels, and snailfish are among fish that live on or near the seafloor—but they occupy different habitats and depths.
4-minute read By Animalso Team

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Fish that live on or near the ocean floor include flatfish, eelpouts, tripod fishes, grenadiers, rockfish, cutthroat eels, and deep-sea snailfish. They do not all live at the same depth or spend the same amount of time touching the seafloor: some rest or hunt on the bottom, while others swim just above it. The deepest confirmed filmed fish in NOAA’s account is a snailfish recorded at 8,336 meters (27,000 feet)—well above the deepest part of the ocean.

What does “bottom-dwelling” mean?

Marine biologists distinguish fish that live directly on the seafloor from those that associate with the bottom but swim above it. Both can be described as demersal, a broad term for fish living on or close to the seabed. The distinction matters: a fish seen in deep water is not automatically a bottom-dweller.

Term Relationship to the seafloor Examples
Benthic Lives directly on the seafloor much of the time. Flatfish, many eelpouts, and tripod fishes.
Benthopelagic Lives in association with the seafloor but spends little time in direct contact with it. Grenadiers, many rockfish, and cutthroat eels.
Demersal Umbrella term covering benthic and benthopelagic fish. Includes both groups above.

These are examples, not a complete global list. Ocean bottoms vary from continental slopes and canyons to seamounts, abyssal plains, hydrothermal vents, and trenches, and there is no single species list that describes all of them.

Examples of fish that live on or near the ocean floor

Flatfish, eelpouts, and tripod fishes

Flatfish are among the clearest examples of benthic fish: they live on the seabed. Many eelpouts and tripod fishes are also benthic, though their shapes and ways of moving differ. The term describes their relationship to the bottom, not one shared body type or depth range.

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Grenadiers, rockfish, and cutthroat eels

Many grenadiers and rockfish, along with cutthroat eels, are described as benthopelagic or demersal. They are associated with the seabed but may swim above it rather than remain in contact with the substrate.

Snailfish and trench habitats

Snailfish occur from coastal waters to deep ocean trenches. Deep-sea members of the group are notable for living at hadal depths—the zone below 6,000 meters. A snailfish holds NOAA’s deepest confirmed filmed-fish record, but that record does not mean all snailfish live near trenches.

Anglerfish: not all are bottom fish

Some anglerfish live close to the seafloor, while others inhabit the bathypelagic water column. In many deep-sea anglerfish, the female has a bioluminescent lure that helps attract prey in darkness. That adaptation is not a feature to attribute to every deep-sea fish or every anglerfish species.

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How deep do bottom-dwelling fish live?

“Bottom” is a habitat description, not a depth zone. A fish can live near the seafloor on a relatively shallow shelf or at great depth. NOAA places the abyssopelagic zone at roughly 4,000–6,000 meters and the hadal zone below 6,000 meters. The ocean floor extends across many depths, so these labels describe water-column zones rather than a single kind of seafloor habitat.

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Record or zone Depth What the evidence says
Abyssopelagic zone 4,000–6,000 m NOAA’s stated depth span for this zone.
Deepest confirmed filmed fish 8,336 m (27,000 ft) NOAA reports a snailfish filmed at this depth.
Historical *Abyssobrotula galatheae* trawl record 8,372 m (27,460 ft) NOAA reports the capture, but the net’s exact depth when the fish was caught is uncertain.
Approximate pressure-related lower boundary for fish About 8,400 m (28,000 ft) NOAA says research suggests pressure may prevent fish from passing this approximate depth.

The filmed snailfish sighting and the older trawl record are different kinds of evidence. The first is a confirmed visual observation at a known depth; the second is a capture whose precise depth is uncertain. NOAA describes the Challenger Deep as reaching about 11,000 meters, deeper than any known fish record. In other words, fish have been observed in hadal trenches, but there is no confirmed fish record from the deepest part of the ocean.

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How do deep-sea bottom fish find food and survive?

Deep habitats are dark, cold, under high pressure, and often far from the sunlit food production that supports much ocean life. These conditions limit available food, so fish adaptations differ by group rather than following one universal deep-sea design.

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  • Attracting prey: In many deep-sea anglerfish, a female’s bioluminescent esca is supported by a modified dorsal-fin ray called an illicium. The lure contains light-producing bacteria and can draw prey close, reducing the need to search by swimming.
  • Ambush: Bottom-associated predators can wait for prey rather than actively pursue it. NOAA’s account of observations near Puerto Rico found a greater proportion of bottom-dwelling ambush predators at greater depths in that study.
  • Body and sensory specializations: Deep-sea groups have different forms suited to their environments. NOAA’s Puerto Rico report noted eel-like body forms among fish in colder, deeper waters; this is a pattern from those observations, not a rule for every deep-sea fish.

What observations show about fish at different depths

NOAA’s March 19, 2026 summary of a study based on 30 ROV and submersible dives near Puerto Rico describes fish observations from 250–6,300 meters. In that regional dataset, fish abundance and biodiversity declined with depth, while the share of bottom-dwelling ambush predators rose. The report also includes observations of fish interacting with the seafloor, such as a skate moving over a dragonet. These results describe one region and set of dives; they are not a census or universal pattern for every ocean floor.

Further reading

For a technical overview of deep-sea fishes, including demersal and pelagic groups, see Imants G. Priede’s Deep-Sea Fishes: Biology, Diversity, Ecology and Fisheries, described by Cambridge University Press as a global treatment of their diversity, evolution, physiology, ecology, and fisheries.

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