Sargassum fish

Histrio histrio

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Lophiiformes
Family: Antennariidae
Genus: Histrio
Species: Histrio histrio

The sargassum fish (Histrio histrio) is a frogfish that has left the sea floor to live in floating seaweed, its mottled yellow-brown body and leafy skin flaps matching the drifting sargassum perfectly. It is the only frogfish adapted to life near the surface.

It reaches about 15-20 cm. Using its grasping pectoral fins it clambers through the weed like a tiny climber, ambushing shrimps, crabs and small fish, and it is a notorious cannibal. It can even gulp air and survive brief stranding on top of the seaweed.

This species is found in tropical and subtropical seas around the world wherever floating sargassum drifts, from the Atlantic's Sargasso Sea to the Indo-Pacific. In the Philippines it turns up among drifting seaweed and debris, and it has been seen by divers there. It relies on the floating seaweed for shelter, food, and protection.

Photo: Dan Schofield, CC BY 4.0, via iNaturalist