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Scuba Your Guide to Diving in Asia Newsletter

Frogfish

Open most marine photography coffee-table books and you're almost certain to see a few pages there dedicated to the regal frogfish. One of the kings of the critters, the frogfish, or anglerfish, is often photographed for several reasons - their various camouflage colours and textures, their incredible, lightening-quick hunting tactics and of course their down-turned mouths.

Few marine creatures are more fun to find when you're diving, usually perched motionless in a squat position in or on sponges whose texture and colour are identically matched by this expert angler; its 2 small, ever-patient eyes keeping watch for the next victim of its lethal, split-second gulp.

Frogfish Fact Sheet

Family name: Antennariidae
Order name: Lophiiformes
Common name: Frogfish or sometimes called anglerfish
Scientific name: Antennariidae

Distinguishing Features

Frogfish, in all their shapes and sizes are named due to their similar appearance to amphibious frogs. They range in size from around 5cm to 40cm. They also resemble frogs in that their fins are sometimes used like legs to walk slowly over the sea bed and atop sponges to position themselves and lie in wait for their prey.

Colour is often no help in identifying different members frogfish family as some have many different colour forms to allow themselves to camouflage expertly within their local environment. Depending on the species, this colour change can take from a few seconds to a few weeks. Some frogfish's skin is also adorned by bumps, warts, flaps and tassles which further allow for mimicking the nearby rocks, sponges or weeds. Their camouflage ability explains why divers often cruise straight past, oblivious to their presence.

Since colouration is an all but useless method of identification for all but the most rare species, you should be looking out for species-specific features such as what form the lure takes, mimicking perhaps a worm or fish, the number of eye spots and spines.

Feeding habits

Perfectly camouflaged and still, the frogfish lies in wait, using its lure to attract prey. They also use a chemical attractant so sometimes they can just lie in wait for some unfortunate fish to swim too close.

When the prey is within range the blitzkrieg attack starts. The frogfish expands its oral cavity, engulfing the prey with a reflex that instantly sucks it in by creating suction pressure inside the mouth. Taking no more than around 6/1,000 of a second, it is the fastest 'gape and suck' reflex of any fish.

They eat mostly small fish but also crustaceans. Being toothless the frogfish swallows its prey whole, allowing its digestive system to do the rest. The prey can sometimes be seen writhing against the walls inside the frogfish's stomach.

Life cycle

There is very little research data on the life cycle of frogfish, but it's difficult to imagine that they live beyond a few years. Certainly their life span in captivity is only a matter of a few years, so in the wild, it is not likely to be much longer.

Not a great deal is known about the reproduction of frogfish either, and in the wild it is a very rare sight to witness. During the process the female fills up with up to 180,000 eggs and her body becomes distorted and buoyant. The male will nudge the female's abdomen as they make their way to the surface where spawning takes place.

Some species guard their eggs, while others release their thousands of eggs as a drifting egg raft. After up to 2 months, the eggs hatch into juvenile, but fully-developed frogfish, with some species types having special defensive colourations.

Frogfish have very little to fear in the way of predation. What eats a frogfish? Other frogfish and moray eels. However, this is a rather rare phenomenon. It is also possible that other opportunistic predators might devour frogfish, particularly when the frogfish are young. More often than not, however, the frogfish is the diner, not the dinner.

Distribution

Frogfish are found throughout the tropical and sub-tropical waters. Most species live in relatively shallow water, although some are deep dwelling. Recreational divers in Asia are most likely to spot certain species including the giant, clown and painted frogfish.

Estimates of numbers of frogfish are difficult to obtain but they are not believed to have declined significantly in recent years. Aside from habitat destruction there is little danger posed by humans. Perhaps the greatest irritant to the frogfish is the constant flashing of photographic strobes, such is the enduring love that underwater photographers have for these fascinating fish.

Areas recognised as muck diving destinations are often the best place to find frogfish. Few places have them in such variety and abundance as Lembeh in North Sulawesi, Mabul in Malaysia.