frogfish

Frogfish – also known as anglerfish – are one of those weird & wonderful underwater inhabitants that divers simply love to discover.  In addition to their superb camouflage, their incredible variety of colour and texture make them fascinating to observe, while their behaviour is equally unusual.  When frogfish bother to move at all, they tend to walk, rather than swim.  They fish – with a lure on the top of their head –  rather than actively hunt, and their down turned mouths and unusual body shape add to a real sense of character.

There are around 45 members of the highly specialised frogfish family.  All frogfish are a similar shape but can vary greatly in size colouration, patterns and markings.

There is a lot of variety within species as well, two frogfish of the same species can have very different markings and colours, making it very difficult to correctly identify many of them.

Despite their differences, most of them share a number of common features; click on the headings below to find out more.

Size

Full grown frogfish vary from the New Ginean frogfish (Antennatus dorehensis) only 5cm to the Giant frogfish (Antennarius commersoni) that can reach 50cm.

Behaviour

Frogfish are ambush predators, catching their food using a lure on a long filament attached to their heads.  As a result, they spend most of their time stationary, waiting for the right fish to take the bait.  Unsuspecting fish are drawn in to investigate what looks like a tasty snack, not noticing the perfectly camouflaged frogfish close behind it.  In a lightning quick action the unlucky prey is sucked into the frogfishes’ enormous mouth.  Because of their unique feeding strategy and their amazing camouflage they rarely need to move to pursue prey or escape predators.  When they do move then often walk on modified fins as legs.  They can swim but rarely do so unless escaping danger or mating.

Distribution

Frogfish are found throughout Asia’s tropical waters.  In certain areas where conditions are very favourable, they can be quite common.

Habitat

Frogfish can be found in a variety of habitats.  They particularly like coastal areas with plenty of algal growth and are often seen on or near to sponges.  They can also be seen on shipwrecks, jetties and artificial reefs.

Diet

Frogfish eat a variety of fish and crustaceans.  Their bones are extremely flexible, allowing them to swallow a fish up to twice their own size.  They have even been known to eat each other.  Although they will happily eat almost any fish they can catch, different species have specific favourites, their lures each mimicking a different appealing snack for passing fish.

Reproduction

As she becomes ready to mate the female starts producing eggs.  As her abdomen swells, she becomes larger & more buoyant, attracting the attention of nearby males.  As her buoyancy increases the male starts to nudge her repeatedly until both float to the surface where the eggs are released and fertilised, forming a floating gelatinous raft.  This raft is usually left to float pelagically, however some species attach the eggs to their bodies and guard them until they hatch.  Juvenile frogfish are pelagic for about 2 months once hatched, after which they settle on a reef.

Defences

The best defence a frogfish has is its camouflage.  Not only is it essential for catching prey, it also helps baffle would be predators.  Most potential predators have great difficulty in picking out a frogfish from the surrounding habitat unless they move.  Frogfish are also able to suck in water and puff up their bodies, making them too large for most predators to swallow.

Threats

Frogfish are not sought after by fisherman and are not threatened by overfishing.  Their greatest threats are loss of habitat & pollution.

Trivia

Although they look slow and ungainly, a frogfish can attack in as little as 1/6000 of a second – the fastest movement in the animal kingdom.

Antennarius commersoni

The giant frogfish is the largest in the family and can grow up to 50cm.  They can vary significantly in appearance to blend in to their habitat and surroundings, but often have growths and warts to help with camouflage.  Identified best by their large size, they are often found perching on the top of sponges or high above the bottom on wrecks or artificial reefs.

Antennarius maculatus

With their colourful designs clown frogfish are one of the easiest frogfish to identify.  Usually yellow or white with black markings these little frogfish can be some of the most striking in their family.  Juveniles also have incredible and easily identifiable markings.  They are sometimes known as the Warty Frogfish.

Antennarius pictus

This species comes in a wide variety of colours and markings, including pink, red, black, white & yellow.  Some have smooth skin with markings that mimic the pores of the sponges they live in.  Others have growths and warts to mimic algae in their environment.  Juveniles also have incredible and easily identifiable markings, often mimicking poisonous flatworms.