opah

fish species, Lampris guttatus

Also known as: Lampris guttatus

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 21, 2026

Quick Summary

The opah, scientifically known as Lampris guttatus, is a large, deep-bodied marine fish found in tropical and temperate oceans worldwide. It is distinguished by its vibrant coloration, featuring blue on its upper body and rosy hues below, with scarlet fins and jaws, and distinctive white spots.1

Remarkably, Lampris guttatus is the only known fish species that is fully warm-blooded. This unique trait is due to a specialized heat exchange system in its gills, allowing its heart to pump faster and its muscles to function more efficiently, providing an advantage in speed for hunting prey like cephalopods and invertebrates. Opahs are valued as food, though they are not commonly caught.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

opah
opah

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

opah
One species, Lampris guttatus, is the only known fully warm-blooded fish. Although two species are recognized traditionally, some classifications suggest that anatomical evidence exists to divide L. guttatus into five species.
Read More
One species, Lampris guttatus, is the only known fully warm-blooded fish. Although two species are recognized traditionally, some classifications suggest that anatomical evidence exists to divide L. guttatus into five species.
Read More