A frogfish that lives in floating weed rather than on the bottom: 20 cm (8 in) of mottled yellow-brown body covered in fleshy tabs that copy the bladders and fronds of sargassum exactly. In a raft of drifting weed it is invisible until it moves.
It climbs. The pectoral fins have a joint that works like an elbow and grip like hands, and the fish hauls itself through the weed rather than swimming, staying inside the raft as it drifts across an ocean.
It eats anything it can fit in, including other sargassum fish. The strike is the family's - a suction gulp in a few milliseconds - and the stomach stretches enough to take prey as large as the fish itself. In captivity a tank of them becomes a tank of one.
It can also survive out of water for a surprising time, and there are records of individuals hauling across exposed weed at the surface. The whole animal is built for a habitat that is not a place at all, but a moving pile of plants - which is why it turns up anywhere the current dumps the weed, including onto beaches after a storm.
The species. Histrio histrio (Linnaeus 1758) - harlequin. ETYFish
- body covered in fleshy tabs and filaments that copy the weed it lives in
- yellow-brown mottled, with dark streaks radiating from the eye
- clings to weed with hand-like pectoral fins rather than swimming
- length up to 20 cm
