The oarfish (Regalecus glesne) is often called the “Doomsday Fish” or “Earthquake Fish” due to ancient legends and recurring observations that link its rare appearances near the surface or shore to natural disasters, especially earthquakes and tsunamis. With its long, ribbon-like body and mysterious deep-sea habitat, the oarfish has captivated both scientists and coastal communities for centuries. Its sudden surfacing, often when dying or dead, has fueled folklore—particularly in Japan, where it is known as the “Messenger from the Sea God’s Palace.” These eerie sightings, sometimes occurring shortly before seismic events, have led to speculation that the oarfish may be a living barometer of tectonic unrest. While science has yet to confirm a definitive link between oarfish behavior and seismic activity, the myth persists, blending deep-sea mystery with cultural memory and geologic fear.
Oarfish
Oarfish – Biological Fact Sheet
Scientific Classification
Common Name: Oarfish
Scientific Name:Regalecus glesne
Family: Regalecidae
Order: Lampriformes
Class: Actinopterygii (ray-finned fishes)
Conservation Status: Not evaluated (IUCN Red List)
Physical Description
Body Shape: Long, ribbon-like, laterally flattened
Length: Commonly 3–8 m (10–26 ft); can grow up to 11 m (36 ft), with some unconfirmed reports of 17 m (56 ft)
Weight: Can weigh over 270 kg (600 lb)
Color: Silvery with a bluish sheen and a distinctive bright red dorsal fin that runs the entire length of the body
Fins: Long, trailing pelvic fins; no caudal (tail) fin in adults
Skeleton: Bony fish, but lacks scales
Habitat
Zone:Mesopelagic (200–1,000 m / 660–3,300 ft deep)
Environment: Worldwide in tropical to temperate oceans
Behavior: Solitary, rarely observed alive; sometimes seen drifting near the surface when sick or dying
Diet and Feeding
Feeding Type: Filter feeder or opportunistic predator
Diet: Plankton, small crustaceans, squid, jellyfish, and small fish
Mouth: Small and toothless, adapted for suction feeding
Reproduction
Reproduction Type: Oviparous (egg-laying)
Spawning: Occurs in the open ocean; eggs float near the surface
Egg Size: ~2.5 mm in diameter
Lifecycle: Little is known; larval oarfish are very different in appearance
Adaptations
Pressure Resistance: Physiology adapted to survive extreme deep-sea pressures
Lack of Swim Bladder: Helps avoid pressure-related problems at depth
Bioluminescence: No; not known to produce light
Sensory Systems: Likely use lateral lines and vision to detect prey and movement
Myths and Cultural Significance
Often dubbed “Doomsday Fish” or “Earthquake Fish”
In Japanese folklore: “Ryugu no tsukai” – the messenger from the Sea God’s Palace
Surface sightings often associated with impending earthquakes or tsunamis (no scientific evidence for causality)
Interesting Facts
World’s longest bony fish
First filmed alive in its natural habitat in 2010 near the Gulf of Mexico
Has no scales—covered in silvery guanine pigment instead
Their death at the surface is usually due to thermal shock, low oxygen, illness, or injury
Oarfish Sketch
Why is it Named Earthquake Fish?
1. Deep-Sea Habitat & Rare Sightings
Oarfish live at depths of 200 to 1,000 meters (660 to 3,300 feet) in the open ocean.
They are rarely seen alive at the surface; when they do appear, it usually signals that something abnormal is happening in their deep-sea environment.
2. Traditional Japanese Beliefs
In Japan, the oarfish is called “Ryugu no tsukai” (龍宮の使い), meaning “Messenger from the Sea God’s Palace”.
Folklore claims that when oarfish rise to the surface, it’s a warning of an impending disaster, particularly earthquakes or tsunamis.
3. Anecdotal Patterns
Some oarfish have been found shortly before major seismic events:
In 2010 and 2011, multiple oarfish were seen in Japan before the 2011 Tōhoku earthquake and tsunami.
Similar reports came before other earthquakes in the Pacific region.
Scientific Explanation
Magma activity under the seafloor—especially near mid-ocean ridges, volcanic vents, and subduction zones—can raise the temperature of deep seawater. However, the effect is localized, not widespread across the entire deep ocean.
How Magma Heats Deep Water:
1. Hydrothermal Vents (Black Smokers)
Found at tectonic plate boundaries, especially mid-ocean ridges.
Magma heats seawater that seeps into cracks in the ocean crust.
This superheated water (up to 400°C) erupts back into the ocean, forming vents.
These are surrounded by unique ecosystems that thrive on chemosynthesis instead of photosynthesis.
2. Submarine Volcanoes
Eruptions on the seafloor can directly release heat and volcanic gases into the water.
Some submarine volcanoes continuously leak heat, warming local deep water layers.
3. Magma Intrusions Without Eruption
Even if magma doesn’t erupt, it can slowly raise the temperature of nearby rock and seawater through conduction and convection.
How Far Does the Heat Spread?
The temperature rise is very localized—typically within a few kilometers of the vent or volcano.
The vast volume and thermal inertia of the ocean quickly dissipate the heat.
Deep ocean water remains cold overall (around 2–4°C), despite many active vent systems.
Scientific Significance
Hydrothermal activity plays a role in:
Mineral cycling (iron, manganese, sulfur).
Heat exchange between Earth’s interior and oceans.
Supporting deep-sea ecosystems without sunlight.
What Happens to Oarfish?
Yes — a sudden hydrothermal or volcanic eruption on the deep seafloor could very realistically trigger a panic response in oarfish, forcing them to flee upward, where they would likely die or become fatally disoriented. This is a plausible scientific explanation for some of the mysterious surface sightings of oarfish.
Let’s break this down in a structured way:
Sudden Subsea Eruption in the Deep Sea
What Happens:
New hydrothermal venting or undersea volcanic eruptions release:
Superheated water and magma.
Toxic gases like H₂S, CO₂, and SO₂.
Sudden turbulence, shockwaves, and pressure changes.
Local oxygen depletion and changes in salinity.
Impact on Deep-Sea Life, Especially Oarfish
Oarfish Experience:
Thermal shock and suffocation due to hot, low-oxygen water.
Disruption of their electrosensory and orientation systems by magnetic or acoustic waves.
Instinctive escape response, likely upward, since lateral escape may not help due to surrounding disturbance.
Ascent to Surface: A Desperate Escape
Oarfish are not equipped for rapid vertical movement:
They have fragile bodies and poor swimming muscles.
Swim bladder cannot adapt quickly to pressure changes.
The ascent causes:
Barotrauma (internal pressure damage).
Loss of buoyancy control.
Neurological damage or disorientation.
Surface Appearance = Final Stage
By the time they reach the surface, they’re:
Severely weakened or fatally injured.
Often floating belly-up or struggling weakly.
They die soon after — and are spotted by humans, often just before or after a seismic or volcanic event, reinforcing the “Doomsday Fish” myth.
Scientific Interpretation:
Sudden undersea volcanic or hydrothermal activity can directly drive oarfish toward the surface in a panic. This could explain some historical and recent surface sightings of dying oarfish, especially when coinciding with tectonic disturbances, without invoking supernatural explanations.
Oarfish found dead
Story of an Oarfish
Title: Messenger from the Depths
At a depth where sunlight had never danced and silence ruled like an ancient god, the oarfish drifted through cold waters. Its ribbon-like body undulated slowly, peacefully. The pressure of the deep was its cradle, and the chill, its comfort. Around it hovered plankton and silent shadows. This was home.
Then, the seafloor beneath him trembled.
A low-frequency growl echoed through the abyss — not sound, but something felt in every fiber of the body. The oarfish froze mid-motion. The sand below split like torn fabric. A vent, dormant for centuries, erupted violently, spewing scalding water and sulfurous gas into the pitch-black sea.
A wave of searing heat punched the water column. Superheated currents tore through the cold like invading fire. Creatures scattered. The oarfish recoiled — but the rising torrent was faster. The temperature rose unnaturally. The water became bitter, suffocating.
Instinct screamed: Escape. Up.
The oarfish surged, muscles straining, ascending into the unknown. It passed species it had never seen. The water grew warmer — not the boiling burn of the vent, but unfamiliar still. The pressure began to drop. It felt like its organs were swelling. The world around it blurred.
Its body, never meant to fight gravity or surface light, began to break down. Internal gases expanded. Its jaw sagged open. Its long, silvery body bent awkwardly. It kept rising.
At last — the surface.
Salt spray. A gleam of moonlight.
The oarfish floated, belly toward the stars, its great eyes wide but unseeing. It was dying — not from a predator, not from age — but from a wound deep in the Earth’s crust.
The next morning, fishermen found it drifting on the tide.
Twenty feet long, silver and red, with a mane like drifting kelp. They stood in awe. “A messenger,” one whispered. “A sign.”
Three days later, the seafloor trembled again — and the coast shook.
Multiple Oarfish Strandings This Month
Three oarfish washed ashore within one week on Pacific shores—two in New Zealand and one in Tasmania, Australia (smithsonianmag.com, theguardian.com). Specimens included two headless fish in New Zealand and one nearly intact nine-foot individual in Tasmania.
The Tasmanian specimen, discovered at Ocean Beach by Sybil Robertson, was around nine feet long and sparked local doomsday fears—though marine biologists emphatically stated no link to natural disasters (theguardian.com).
