One of the world's oddest-looking underwater creatures, you shouldn't be fooled by the hairy frogfish's name - it is a fish, not a frog, and it isn't actually hairy.
The hairy frogfish, or striated frogfish (Antennarius striatus), is a moody-looking, puffball-like sea dweller that is covered in spines. But the fact that it looks weird is not the only strange thing about it.
What is a hairy frogfish?
The hairy frogfish is a type of carnivorous fish that lives in warm ocean waters. It is covered in spines that look a bit like out-of-control hair.
Hairy frogfish have excellent camouflage – they are able to change colour to fit their surroundings – and they don't actually swim.
How big are hairy frogfish?
The hairy frogfish can grow up to 23cm long and weighs around 33g. It has a rounded body with soft skin covered in spines. Despite its relatively small size, it is an adept predator, with a big mouth that is able to swallow prey as large as itself.
What do hairy frogfish look like?
Weird! The hairy frogfish generally looks quite grumpy thanks to its upturned mouth, which it can extend or expand forward. The body (and stomach) is also extendible and covered in spines, which look a bit like a mass of waving hair – although it doesn't actually have any hair.
The hairy frogfish has an adapted dorsal spine, which is moveable and acts as a kind of fishing rod that looks a bit like a worm – great for attracting prey. It usually has striped or streaked markings on its body, which it can change, along with its colour, to match its surroundings.
It also has the ability to mimic other species, such as sea anemones, to scare off other predators from attacking it. It can take a hairy frogfish a few weeks to change its colouration.
What do they eat?
Pretty much whatever they can get their formidable jaws around. The hairy frogfish is a voracious predator and carnivore and will eat crustaceans and other fish – including fish that are about the same size as themselves. The hairy frogfish has been known to eat its own kind, too.
How do they hunt?
Exceptionally well and in two different ways. The hairy frogfish's ability to camouflage means it can sit still in an area and look just like a bit of coral or seaweed until a fish or crustacean swims by and it grabs them.
It also attracts prey by waggling its long, adapted dorsal fin, which looks very much like a worm – this attracts the attention of fish, which swim closer and closer until the hairy frogfish grabs them with its incredible jaws. If the prey isn't interested in the worm-like dorsal fin, the hairy frogfish will stealthily move forward to get closer to its victim.
Once the prey is close enough – about one body length away – the hairy frogfish is able to propel itself onto its prey and swallow it whole by extending and lowering its jaw. They are incredibly speedy and manage to inhale their prey in six milliseconds. They have tiny teeth on the roof of their mouth, which are not used for eating but are used instead for holding onto their prey.
Where do they live?
Hairy frogfish live in shallow, sandy areas where there are rocks and coral reefs, as well as deep waters. They are found in the Indo-pacific and eastern Atlantic Ocean, but their habitat is at risk due to rising ocean temperatures, which is affecting the spread and colouration of coral.
How do they move?
Although they don't move much, hairy frogfish have an incredible ability to propel themselves along the ocean floor very quickly using their huge mouth and gills – a bit like jet propulsion. But they also have wide, jointed fins, which they use to push themselves across the ocean floor, rather than swimming, which their fins are not adapted for. So, you could say that they walk on the ocean floor, rather than swim.
How do they reproduce?
Generally, hairy frogfish are solitary animals and avoid other frogfish, apart from when mating. When a female frogfish is ready to mate, her and the male swim up to the surface where she releases her eggs in a kind of gelatinous raft and the male fertilises them. The eggs usually sink down to the bottom of the ocean after a few days when the embryos are ready to hatch.
Top image credit: imageBROKER/Detlef Denne imageBROKER/Getty Images
