FishRare

Commerson's frogfish

Antennarius commerson

The reef's greatest master of disguise: Commerson's frogfish impersonates a sponge and lures its prey in with its very own fishing rod.

Photo: iNaturalist – (c) uwkwaj, some rights reserved (CC BY-NC), uploaded by uwkwaj

Commerson's frogfish (Antennarius commerson) is the largest frogfish on the coral reef – and arguably the ocean's finest camouflage artist. Its chubby, almost globular body has a leathery, granular surface, and its colour can shift over a few weeks to anything from yellow, orange and red to grey or near-black, matching whichever sponge it has settled beside. Its first dorsal spine has evolved into a genuine "fishing rod" (illicium) tipped with a fleshy lure, which it waves right in front of unsuspecting small fish.

Its strike is one of the fastest movements in nature: when a fish snaps at the lure, the frogfish's enormous mouth expands in roughly six milliseconds, and the sudden vacuum simply sucks the victim in. Its stomach is so elastic that it can swallow prey as large as its own body. It rarely bothers swimming – instead it slowly "walks" across the bottom on arm-like pectoral fins, like a grumpy little toad.

Around Hurghada it is a rare, genuinely prized find – dive guides pass the news along whenever one turns up. Look for it beside sponges, on wrecks and along shaded wall sections, scanning slowly with a trained eye. If your guide points at an "empty" sponge, look twice: chances are a pair of eyes is looking back at you.

Did you know?

A frogfish strike takes about 6 milliseconds – one of the fastest movements ever recorded in a vertebrate. Fish swimming right next to the victim often never notice their shoalmate has vanished.

Where can you meet it?

Your best odds are on the sponge-covered El Mina wreck and the shaded walls of El Fanadir, though it occasionally turns up on the deeper sections of Umm Gamar too.

Frequently asked questions

Not to humans at all – it has neither venom nor any interest in you. The risk runs the other way: it is so well camouflaged that it is easy to kneel or lean on one, which is one more reason never to touch down on the reef.

Practically no – frogfish hide deeper among sponges and wrecks and are impossible to spot from the surface. This is a classic scuba encounter, best achieved with a sharp-eyed guide.

Move slowly and search not for fish but for "suspiciously regular" shapes on sponges: a downturned mouth line, a tiny eye. Most frogfish are found by guides who know exactly which sponge one lived on last week.