Hairy Frogfish

FishCosmopolitan

10 Jan

Antennarius striatus

The hairy frogfish doesn't pursue prey. Instead, it wobbles along the sea floor, finds a hiding spot, and uses a worm-like appendage on its head to lure in a victim. Its body is covered in spines which resemble strands of hair — camouflaging it amongst seaweed, assisted by colour-changing abilities.

Have you ever gone diving, watching all the colourful fish swim by — adorable little clownfish frolicking in the anemones and hypnotically-coloured angelfish — and just wished you could spot something more exciting, something completely wacky? Say, like a giant hairball with eyes and a mouth? No? Well, that's too bad, because the hairy frogfish exists and it's probably in an ocean near you. This wonderful abomination of nature exists along most of the world's shorelines ¹, or at least those where most people enjoy swimming, since it's a fish of the tropics and subtropics — like us, it likes its warm waters.

If you saw one, you'd almost be hesitant to call it a fish. You'd look at it and go: "That's not a fish, that's a weird rock with some seaweed on it." Then it would pop out its beady eyes, and open its gaping mouth into a massive frown. It would dislodge from its hiding spot, exposing a malformed "hairy" body about the size of a large potato ², and it would wobble away along the sea floor. You might watch it sautner awkwardly and say: "I don't know what that is, but that's still not a fish!" But a fish it is. The hairy rock, trudging slowly across the sand, really does look like a piece of reef brought into an unfortunate existence, but that's all part of this fish's strategy. You'd have to be either very perceptive or lucky to spot it. Otherwise, just content yourself knowing that, the next time you go for a dip, a hairy frogfish is probably nearby. You just can't see it, for it is a master of stealth.

I'm Just a Part of the Scenery

The hairy frogfish is not a looker because it doesn't want to be looked at. Its body is completely covered in spines ³ which resemble flowing strands of hair (hence the name) or more accurately, and usefully given its environment, they resemble the waving leaves of seaweed. It can inhabit the shallows some 10 metres (33 ft) below the surface, and live all the way down near the borders of the twilight zone at 200 metres (655 ft) — although its preference, its Goldilocks zone, seems to be around 40 metres (130 ft). Here it lives amidst drab sands and rocky rubble or, contrastingly, in the most colourful habitats on Earth, coral reefs. How does one fish manage to hide itself in such opposing extremes of colour? Is a hairy frogfish, born to a reef, barred by its gay complexion from living amongst sandy stones? No. A hairy frogfish can relocate from reef to rock and back — as well concealed in one habitat as the other.

Like a chameleon or cuttlefish, the frogfish can change the colour of its body. Unlike a chameleon or cuttlefish — who can do so in under a minute in the case of the former, or a few milliseconds in the case of the latter — the frogfish takes several weeks to complete its colour-shifting transition. So a move from one type of habitat or hiding spot to another is a deliberate decision (as deliberate a decision as a fish can make) that must be committed to, quite literally, with all of its body. What the frogfish's camouflage lacks in speed, it makes up for in variation; capable of changing from a sandy grey or brown to bright orange, yellow, or green, able to add or remove stripes, and even become completely pitch black. In addition to changing colour for camo purposes, it can also pretend to be a completely different, more dangerous sea creature (in what's known as 'Batesian mimicry'), such as a venomous radiant sea urchin, to make itself less appetising.

If a predator, like a lizard- or scorpionfish, deduces that a hairy frogfish isn't a deadly urchin or just a part of the scenery, but potential prey, the frogfish isn't doomed. Firstly, the frogfish makes itself as intimidating as possible by spreading its fins, opening its mouth, and bending towards its aggressor in a kind of fish version of a shrug. And secondly, it inflates its body with water like a pufferfish, making itself more difficult to swallow. Personally, I'd be put off, if my prospective meal did that.

Underwater Angling

The hairy frogfish is a proficient predator in its own right, if not a very active one. You may associate fish with swimming — what better way to get around underwater? Probably none, so most fish do swim. The hairy frogfish, however, is one of the exceptions. The pectoral fins of a frogfish, rather than controlling speed or facilitating side-turns, have been adapted for walking along the sea bed. It wouldn't be farfetched to call them a set of proto-arms as they're often splayed out to the fish's sides, featuring elbow-like joints and all, while smaller pelvic fins prop up the frogfish from behind. The set-up is interesting, but not built for speed. So, as a predator, the frogfish isn't chasing down anything faster than a worm (or another slower frogfish, to indulge in some casual cannibalism). It doesn't have to, however. Its camouflage makes it an ideal "sit-and-wait" hunter — less a spearfisher and more an angler.

The analogy is more fitting than you might expect. The frogfish has a rod and a lure, some bait, and the patience of a dad with a cooler full of Coors Lights. Its fishing gear is a highly adapted dorsal fin protruding from the tip of its snout. At the end of the stiff rod (called an illicium) this fish has a semi-permanent bait (the esca) which looks like a pink worm. While the hairy frogfish sits immobile and invisible among coral, seaweed and rocks, it casts its rod and dangles its baits, enlarging it by some 35% to make the fat "worm" more appetising. And the frogfish goes a step further than human anglers; it positions itself in front of a water current and, if its juicy bait isn't already alluring enough, the fleshy appendage secretes a chemical attractant that circulates through the water, promising a tasty meal to nearby fish and crustaceans.

It is an invitation to a meal, in a sense. As a shrimp or goby approaches closer, the frogfish follows its soon-to-be victim with beady eyes. It wriggles its wormy bait more and more avidly in what's been described as "aggressive mimicry." Once the hapless prey is within one body length of the frogfish, the angler's maw gapes open to 12 times its initial size, and the victim is sucked inside — going from swimming free to swallowed in a matter of 6 milliseconds (the fastest gape-and-suck feeding of any fish). The poor soul struggles inside its fleshy prison, but specialised muscles in the frogfish's oesophagus close tight around it. The prey's thrashing struggle is sometimes visible through the stomach walls, as digestive juices slowly break it down.

But the frogfish isn't always successful in its angling. Sometimes a speedy fish gets a bite of its bait — not a big deal, the wormy appendage can be regenerated again and again — but sometimes the prey just isn't interested in the bait, despite the aggressive wriggling and the alluring "smell." In that case, the frogfish stalks its target, its body kept low as it slowly gropes along the ground with its weird fin-feet, until it gets close enough to vacuum up the victim. And if the victim is larger than expected? The frogfish simply expands its stomach, allowing it to swallow prey up to twice its own size.

Mini-Males & Mucus Rafts

A hairy frogfish male (red) next to a larger female (yellow).

This goofy-looking thing turns out to be an alien-esque nightmare-creature. I feel the need to mention now that the largest of females only grow to about 25 cm (9.8 in) long, while the males are much smaller — closer to 12 cm (4.7 in). When the time comes for frogfish to spawn, pairs of them can be seen marching across the sea bottom, with the big females followed close behind by their little male mates. And the females are even bigger prior to spawning, swollen up to twice their regular size because they're packed full of eggs. In a "romantic" crescendo, frogfish pairs dash towards the surface where the females expel their egg masses and the males release their fertilizing gametes. The eggs then float around, clumped together in buoyant masses of mucus called "egg rafts," until they hatch.

Deep-Sea Relations

Big females and tiny males, a weird globose body, and a hunting lure on its head — the frogfish is beginning to sound a lot like another monstrous sea creature. One from the abyssal ocean depths.

The frogfishes ⁴ themselves form a family (Antennariidae) with over 50 different species. Not all frogfish are "hairy," but all employ some kind of camouflage to hide and to hunt. The warty frogfish is covered in many wart-like lumps that make it a convincing bit of coral. The Sargassum frogfish spends its life floating among Sargassum seaweed, which its frilly body very much resembles. The longlure frogfish is colourful and lumpy, like the sponges that it likes to hang around with. The tiny and rotund body of the pygmy frogfish looks like a pebble engraved with numerous curving line patterns, and it correspondingly lives among rocky boulders or under rubble. Meanwhile, the psychedelic frogfish must rely on the pure colourful chaos of a coral reef to disguise its garish body, decorated with many swirling, hypnotic stripes — unlike other frogfish, it doesn't even bother changing its colour to match its environment.

A warty frogfish (*Antennarius maculatus*).

A sargassum frogish (*Histrio histrio*).

A longlure frogfish (*Antennarius multiocellatus*).

A psychedelic frogfish (*Histiophryne psychedelica*).

These masters of disguise are all members of a larger order called the Lophiiformes — also known as anglerfish. Yes, the frogfish are related to the unsightly fishermen (or more accurately, fisherwomen) of the deep, a group of over 200 species. They can appear rounded like a flattened basketball, or oblong like a fleshy gourd, long and skinny like an eel, or fat in the middle but tapering towards each end like some kind of deep-sea spindle. These multi-shaped monsters are the females of the species. While male frogfishes might look a little petite next to their female counterparts, deep-sea anglerfish exhibit some of the most extreme sexual dimorphism of any animal group, with the female humpback anglerfish, for example, growing up to 20 centimetres (7.9 in) long, while the male is only some 3 cm (1.2 in). A tiny lure-less male would have a hard time fending for himself in the harsh abyssal world, and he doesn't — he's a sexual parasite; once a male finds a female, he attaches to her body and never lets go, essentially becoming a part of her.
Some deep-sea anglers can live as deep as 2,500 m (8,200 feet), in a world completely devoid of sunlight, where light itself (produced biochemically) has become a valuable tool for communication, camouflage, and hunting. Instead of a fat pink worm on the end of its lure (which wouldn't be visible in the dark), a deep-sea anglerfish dangles a glowing esca that burns like a blue willow-wisp in a pitch-black forest. Nearby fish are attracted to the light — perhaps they think it's a smaller fish that's glowing to communicate and inadvertently giving away its location. They swim up, hopeful for a meal, only to become one themselves as they're engulfed in an angler's toothy maw.
The rest of the anglerfish order is just as diverse in shape and form as those of the deep sea; a hodgepodge of awkward squatters, frilly pancakes, and lunar landers. The anglerfish seem united as much by their sheer bizarreness as they are by their lures and fishing hobby.
The sea toads don't so much have fishing rods as bioluminescent baubles that protrude from their heads like tiny, upright toilet brushes. Most sea toads are, at least to me, significantly more charming than their sea frog (frogfish) cousins, such as the comically bulbous, big-lipped, and bright red Chaunacops roseus. The family is split into two groups; the sea toads, typically found at deeper depths (as deep as 3,300 m/11,000 ft), and the coffinfishes, which are, unfortunately, more fond of shallower waters (as shallow as 50 m/165 ft). I say "unfortunately" because many species in this second genus, like the furry coffinfish, are about as charming as corpses. Frog or coffin, these fish typically live on the seafloor where, instead of swimming, they save energy by ambling around on their large fins.
Such benthic (bottom-dwelling) behaviour is actually predominant among the anglerfish. After all, if you can lure prey to you, why swim at all? A prime example is the handfish family. Most of these small (~10 cm/~4 in) and rare fish, like the critically endangered spotted handfish, live in the sunny shallows around Australia, between depths of 5 to 15 metres (15 - 50 ft). Although handfish can swim in short bursts, they prefer to "walk" along the sea floor on their "hands" — highly adapted pectoral fins which splay out to their sides and resemble, well, hands. Most of the 14 known species also sport large unfoldable crests on their heads, like the crests of cockatoos (there's even a cockatoo handfish). The handfish are ambush predators, and in front of their pompous headpieces, just above their mouths, they have their small "rods and lures," although, in the case of handfish, it's unclear if this structure is actually used for angling prey (shrimps, amphipods, and worms) or perhaps reserved for courtship behaviours or maybe something else altogether.
Take an alien, fuse it with a UFO, put it in the ocean, and you'll have something resembling a batfish. Like handfish, batfishes crawl along the ocean floor — anywhere from the shallows to 4,000 metres (13,100 ft) deep — although their fins less resemble hands than the legs of a tripod (or quadropod, technically, since they usually stand on four fins). Their tongue-twister family name, Ogcocephalidae, stems from the Greek ogkos, which means “hook”, and cephalus, meaning “head”, in reference to the horny, often decurved projections that jut from the heads of some of the 60 or so species. In addition to their "horns," batfishes have sparkling lures which, like those of hairy frogfish, can emit a fluid (a chemical attractant) into the water. Most batfishes grow to about 20 cm (7.9 in) long, although larger species, like the shortnose batfish, can grow to nearly 40 cm (15.7 in). The red-lipped batfish is probably the most well-known and...attractive species. Below its big knobby "nose," surrounded by some patchy hair-like "stubble," this batfish has a pair of fluorescent red lips. Males are believed to use this this puckered up look to attract mates.
Lastly, there are the ghastly-looking goosefishes, which lie on the floor of every ocean but the Antarctic, with most of them having flattened bodies framed by fractal-like frills. They typically live at depths below 200 m (660 ft) and use movable lures, which look like little fleshy flags, to attract prey into their gaping mouths. Their name, the goosefishes, supposedly comes from an old belief that these bottom-dwellers could swallow a goose whole, but although they can become quite hefty — the largest of these pancake fish being up to 1.2 metres (3.9 ft) long — they're quite unlikely to encounter any geese.
From giant "fowl-swallowing" goosefishes, to lip-stick-wearing batfishes, to "walking" handfishes, spheroid and chronically frowning sea toads, nightmarish deep-sea anglers, and a kaleidoscope of fashionable frogfishes, the anglerfish are certainly among the most interesting and eclectic, if not the most attractive, of all fish families.

A black seadevil anglerfish (*Melanocetus* sp.)

The many shapes of deep-sea anglerfish species.

Left to right; a sea toad (*Chaunacops roseus*) and coffinfish (*Chaunax suttkusi*), a spotted handfish (*Brachionichthys hirsutus*) and red-lipped batfish (*Ogcocephalus darwini*), and American goosefishes (*Lophius americanus*).

¹ The hairy frogfish lives along the eastern coast of North America, throughout the Caribbean, and down the coast of Brazil. It is found in the waters around Hawaii and most of Japan, all of Southeast Asia and Oceania, across the shores of southern Asia, the Arabian Peninsula, most of Africa and possibly along the Atlantic coast of Iberia. Much of the world gets to enjoy the hairy frogfish's company — aren't we lucky?

² The size of a large potato, in this case, is around 20 cm (7.9 in). The largest hairy frogfishes (all large ones being females) grow to lengths of no longer than 25 cm (9.8 in).

³ The "hairs" of a hairy frogfish are technically 'dermal spinules' — spiny extensions of its skin. As people have varying hairstyles, from bald to luscious locks, the spines of individual hairy frogfish can also vary; they can be so short and sparse as to be almost invisible, or copious, long tresses that wave with the currents.

⁴ Frogfish seem to be named for their vague resemblance to the amphibians and the way that they, abnormally for fish, waddle around on the sea floor (although they don't hop like frogs).

**Where Does It Live?**

⛰️ Rocky and sandy areas, as well as coral reefs. Usually between depths of 40 and 210 metres (130 - 690 ft).
📍 The eastern coast of North America, throughout the Caribbean, and down the coast of Brazil, in the waters around Hawaii and most of Japan, all of Southeast Asia and Oceania, across the shores of southern Asia, the Arabian Peninsula, most of Africa and possibly along the Atlantic coast of Iberia. ¹

Size // Small
Length // Up to 25 cm (9.8 in)
Weight // Up to 33 grams (1.16 oz)
Activity: Crepuscular 🌅
Lifestyle: Solitary 👤
Lifespan: 15 - 20 years
Diet: Carnivore
Favorite Food: Crustaceans and fish 🐟
Class: Actinopterygii
Order: Lophiiformes
Family: Antennariidae
Genus: Antennarius
Species: A. striatus

A hairy frogfish is about the size of a large potato, which in this case, means around 20 centimetres (7.9 in) long. The largest females — and all large frogfish are females — reach a length of 25 cm (9.8 in). The males are usually quite a bit smaller.
The hairy frogfish can change its colour to match its surroundings — whether that be colourful corals or drab sands — however, this colour-shifting process can take several weeks.
This fish can go from a sandy grey or brown to bright orange, yellow, or green, able to add or remove stripes, and even become completely pitch black — which, with its spike-like "hairs," can make it appear like a deadly sea urchin. Otherwise, its hairy appearance does a good job of mimicking a rock overgrown with seaweed.
The "hairs" of a hairy frogfish are technically 'dermal spinules' — spiny extensions of its skin. The spiny "hairstyles" of individual hairy frogfish can vary; they can be so short and sparse as to be almost invisible, or copious, long tresses that wave with the currents.
The frogfish is a "sit-and-wait" predator. It dangles forth a lure on its head that resembles a worm, fattening it up by some 35% and wriggling it around to make it more appetising, all the while secreting a chemical attractant that draws prey to the bait.
Once its prey is near, the frogfish's maw gapes open to 12 times its initial size, and the victim is sucked inside in a matter of 6 milliseconds — the fastest gape-and-suck feeding of any fish. Sometimes, the prey can be seen thrashing about within the semi-translucent walls of the frogfish's stomach.
To defend itself from a threat, the frogfish spreads its fins, opens its mouth, and bends towards its aggressor in a kind of fish version of a shrug. It can also inflate its body with water like a pufferfish, making itself more difficult to swallow.
The pectoral fins of a frogfish, splayed out to its sides and featuring elbow-like joints, are adapted for walking along the sea bed. The speed of travel on these proto-arms, however, is underwhelming.
The hairy frogfish might live along a coastline near you. Its range follows the Atlantic coast of the Americas, encircles most of Oceania, as well as South and Southeast Asia, around the African continent and possibly up to the coasts of Iberia.
The hairy frogfish can live anywhere between 10 metres (33 ft) below the surface, all the way down to the borders of the twilight zone at 200 metres (655 ft) — although its Goldilocks zone seems to be around 40 metres (130 ft).
Frogfishes, if their dangling lures didn't give them away, are anglerfish. They're related to the bioluminescent nightmares from the deep sea, as well as a panoply of odd ovals, pancakes, and lipstick-wearing fish.