# Oarfish (*Regalecus glesne*)

> The oarfish (Regalecus glesne) is the world's longest bony fish, a ribbon-shaped mesopelagic wanderer that can exceed 8 m. It eats krill and small fish, occasionally strands after storms, and likely inspired some sea-serpent folklore. Listed Least Concern because it lives across the deep open oceans.

- **Category:** Fish
- **Conservation status (IUCN):** Least Concern
- **Range:** Deep open oceans worldwide; occasionally washes ashore after storms.
- **Canonical page:** https://globalanimalguide.org/animals/oarfish/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Actinopterygii
- **Order:** Lampriformes
- **Family:** Regalecidae
- **Genus:** Regalecus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Regalecus glesne |
| Diet | Carnivore (krill and small fish) |
| Habitat | Open ocean mesopelagic zone |
| Lifespan | Around 20 years in the wild (varies by population and captivity). |
| Weight | About 150 kg typical adult mass (sex and region vary). |
| Top speed | Up to roughly 10 km/h when moving at speed. |
| Conservation status | Least Concern (IUCN) |

## Ribbon of the twilight zone

Extremely elongated, laterally flattened bodies with a bright red dorsal fin crest give a serpentine silhouette. They often hang vertically in the water column. No caudal fin in the usual sense — the body tapers.

## Krill in the mesopelagic

Diet centres on krill, other planktonic crustaceans, and small fish sifted in open water far from shore. Across its range it is tied to open ocean mesopelagic zone, and field accounts emphasise this species’ distinctive ecology rather than generic habitat labels.

## Worldwide deep oceans

Mesopelagic zones of oceans worldwide; living animals are rarely seen except by ROVs or when sick individuals wander into shallows and strand.

## Folklore made flesh

Least Concern with a vast pelagic range. Strandings after storms fuel sea-serpent stories; there is no evidence they attack ships or divers.

## Frequently asked questions

### What is the longest bony fish?

The oarfish Regalecus glesne, with reliable lengths beyond 8 m.

### Do oarfish attack boats?

No — they are gentle pelagic filter-feeders of small prey; serpent myths are misidentification.

### Why do oarfish beach themselves?

Illness, storms, or navigational errors in shallow water; healthy fish normally stay offshore at depth.

### What do oarfish eat?

Krill, small crustaceans, and small fish.

### Where do oarfish live?

Deep open oceans worldwide in the mesopelagic zone. Native range summary: Deep open oceans worldwide; occasionally washes ashore after storms.

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Source: Global Animal Guide (https://globalanimalguide.org/animals/oarfish/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.