Frogfish (family Antennariidae)

I was convinced I had to blog about these fish as soon as I saw their name. It immediately conjured images of strange frog-fish hybrids, which of course would never happen. It turns out that the name frogfish is one of the least interesting things about these guys. Frogfish are actually anglerfish, and make up the family Antennariidae.

Frogfish are found pretty much anywhere in tropical or subtropical waters, in both oceans and seas. The most dense area of frogfish species is around Indonesia, where nine different species were found in a single strait. Frogfish like to live in and around coral reefs, and rarely stray deeper than 100 m.

Describing frogfish as a group is fairly difficult, because they are so varied in appearance. They are generally stout, looking more like irregular round balls than fish. They range in size from 2.5 to 38 cm long. Many species are covered in spinules, which can take the form of bumps or spine-like projections. Colours in frogfish can differ both between and within species, and can include white, yellow, red, green, and black.


A well-disguised frogfish. You can barely even tell that this is an animal. Image credit: Stephen Childs via Wikipedia

Frogfish are so different in appearance because they are masters of camouflage. These fish don’t have scales or any other form of protection, so they rely on their disguises to keep them safe from predators. Frogfish successfully imitate coral and stones, sponges, sea urchins, and seaweed. Sea slugs have been so fooled by frogfish camouflage that they have crawled on them, completely unaware that they were actually moving on top of living fish.

Another excellently disguised part of frogfish is their escas, or lures. These can take the form of a number of different ‘creatures’, including fish, shrimp, and worms. Frogfish use the lures to entice prey into approaching to a fatal distance. They hunt a variety of prey, such as crustaceans, fish, and other frogfish. Frogfish can expand their stomachs, allowing them to eat animals twice their size. Frogfish will wave their lures around, mimicking the movements of the animal the lure is disguised as. When the prey gets close enough, the frogfish open their jaws in a rapid motion, which sucks the prey inside. This action occurs extremely quickly, in as little six milliseconds.


A crazy-looking frogfish with a nice fat worm as a lure. Image credit: Jens Petersen via Wikipedia

This is about the only movement frogfish do quickly. The rest of the time, they walk ponderously across the ocean floor, if they move at all. Though frogfish can swim, they prefer to walk along the ocean floor, either in an ambling walk or a kind of gallop. If given a choice, however, they would choose not to move, and lie still waiting for prey to approach.

Though I’ve written about a number of camouflage experts, I think frogfish are probably some of the best around. It’s a shame they aren’t actually a cross between frogs and fish though, like I initially thought. They’re still super cool though!

Cover image credit: Tanaka Juuyou via Wikipedia

Red-Lipped Batfish (Ogcocephalus darwini)

There are some very, very strange animals in the world. Unfortunately many of these animals live in wonderful and strange places, and so are difficult to study. Most of the time when I want to blog about one of these creatures, I choose not to, because there’s just not enough information to make a decent post. Still, sometimes an animal is just too cool, and I can’t resist. Such is the case with animal of today, the red-lipped batfish.

There are two different families of batfish, but the one to which the red-lipped fellow belongs is Ogcocephalidae. They are bottom-dwelling deep sea lovers, and are called batfish because of their flattened bodies. The red-lipped batfish is even more descriptively named, as it has stylish bright red lips. They are pretty fabulous. Red-lipped batfish live on the sea floor near that ecological wonder, the Galapagos Islands. Is it any surprise then, that they are probably some of the weirdest fish out there?

You are not a normal person if you don't think this fish looks strange.

You are not a normal person if you don’t think this fish looks strange. Image source:

They are a little like anglerfish, who use a lure to attract prey. Unlike anglerfish, however, the batfish does not have a luminescent lure. Instead, a horny projection on top of its head releases chemicals that are thought to attract prey. The red lips of the batfish have an unknown function, although there is a theory that they help with recognition of other batfish and with mating. Who wouldn’t want to mate with this:


Red Lipped Batfish

Image credit: Birgitte Wilms, National Geographic


By far the strangest thing about the red-lipped batfish is its method of locomotion. Despite being fish and living in water their whole lives, red-lipped batfish are terrible swimmers. They don’t even bother with it. Instead, they use modified pectoral and pelvic fins to ‘walk’ along the sea floor. It looks pretty ridiculous. But I guess it suits these guys, for they seem to do fairly well, and are not currently threatened or endangered.

So there you have it, probably one of the weirdest fish you’ll ever hear of. I go out of my way to find strange animals and still can’t get over how ridiculous the red-lipped batfish is. Hopefully you now appreciate them as much as I do!

Cover image source:

Leafvent Anglerfish (Haplophryne mollis)

Fish are strange creatures. Most of them are funny looking, some are downright ugly and a rare few are beautiful (I’m thinking of tropical fish shimmering with bright colours on a reef). But still, I think very few people would classify fish as ‘cute’ or ‘pretty’. And few fish are uglier than the subject of today’s post, the leafvent anglerfish.

Most anglerfish are fairly ugly and scary (think of that scene in Finding Nemo), but the leafvent has an extra level of weirdness. It is a largely translucent fish, making it look even stranger. Here’s a picture:

A leafvent anglerfish, looking particularly charming

A leafvent anglerfish, looking particularly charming

Leafvents are, like all anglerfishes, deep sea creatures. They swim slowly in the darkness, using a bioluminescent lure to attract smaller fish which it then gobbles up. This deep sea lifestyle is the reason for the leafvent anglerfish’s lack of colour; there isn’t much need for pigmentation when the world you live in receives no source of light.

The leafvent angler has another important adaptation to deep sea life, involving reproduction. Being very slow-moving fish, leafvents have no easy time finding mates in a vast world of cold darkness. So when these lonely animals do find a mate, they make the most of it.

Female anglerfish are much, much bigger than the males. When a male finally encounters a female, he bites her and holds on with his teeth. Eventually, the two animals fuse, and the male transfers sperm into the female. But after this mating, the male doesn’t let go. Instead, he stays attached, and does so for the rest of his life. The male loses his eyes, jaw, teeth and fins, and is basically a pair of testes sticking off of the female, supplying her with a constant supply of sperm. If that isn’t an odd way to live your life, I don’t know what is.

A female leafvent with two males attached to her

A female leafvent with two males attached to her

The female’s blood has more than enough nutrients to keep this modified sex organ alive, and it’s not uncommon to see a leafvent female with more than one male attached. Though it seems like an unhappy fate for the males, it is a useful way to ensure the female always has sperm, when finding mates is such a chancy affair.

I’ve never seen a fish quite so ugly as the leafvent anglerfish. Even things like the blobfish have a certain twisted charm to their looks. Maybe her poor looks are the reason that males lose their eyes once attached to her! In any case, ugly or not these fish are certainly interesting, and I’ve had a fine time blogging about them.