The Angler Fish: A Mystery of The Deep

It’s no wonder the humpback anglerfish has become immortalized in pop culture

With impact cameos in film and TV and logos on famous surf brands, the anglerfish’s demonic appearance presents irresistible scope for creatives.

In the back of your mind, you probably have seen this creature somewhere…

Its unique form is surely hard to forget. If you came here to know more about this strange creature… then you came to the right place!

These creatures are horror movie ugly

They have beady eyes, a sort of squat shape, and their mouths are grotesquely large relative to their body.

But that’s just the tip of the iceberg… 

Unique Feature of the Anglerfish

They use a built-in rod to dangle a luminescent ball in front of their mouths. The glowing ball serves as a lure or bait for curious prey…

These creatures seem to be in a constant state of angry-face. No doubt upset that mother nature has bestowed it with such crowd-pleasing good-looks. 

What’s more, it lives in the deep dark ocean where it’s super tough to make friends and find dinner.

You’d be grumpy too right?

A Type of Anglerfish on Display in a Market
A Type of a Bottom Dweller Anglerfish on Display in a Market

The Anglerfish Family

Today our focus is on the deep-sea anglerfish or ‘Melanocetus johnsonii’, its scientific name…

It gets its common name “anglerfish” from its hunting method, which we’ll discuss a little later. These sea animals are also known as black seadevils and Johnson’s anglerfish.

It shares the anglerfish name with a great many of its extended family, yet there are many differences between family members…

Interestingly, their kind comes from a pretty big family of over 200 species. 

But here’s the interesting thing

Variety of Anglerfish

Some of them are benthic, or bottom dwellers

Others, including deep sea anglers are pelagic or swim away from the ocean floor. You’ll find the whole, big extended family spread out around the world. 


Many of the deep-sea angler’s benthic cousins look quite different. They are dorsoventrally compressed. This means their entire body is compressed as though it has been stood on.

This is a well-suited shape for living and hunting on the ocean floor – much like a flounder or a stingray.

Deep-sea anglers are laterally compressed, like trevally for example – but that’s the end of its resemblance to anything…well, normal, anyway…

Think I’m exaggerating?

Scary Features

Deep-sea anglers have small beady zombie-looking eyes, adding further menace to its evil visage

Its fins actually look useless for swimming. They’re ragged and appear poorly placed as if evolution began ignoring them countless millennia ago…


While deep-sea anglers look like they would scare the scales off a great white shark, They are relatively small fish, growing to around 5 inches when fully mature – smaller than a normal-sized adult hand.

By Ryan Somma - Flickr, CC BY 2.0,
Melanocetus Johnsonii(2)

A built-in fishing pole

Deep-sea anglers clearly have some stand-out physical features. Perhaps the most unique, however, is its inbuilt fishing rod.

Protruding from its head…or face…it’s kinda hard to tell, is a fishing rod type organ with a bioluminescent ball on the end. 

In the finest traditions of symbiotic relationships, the glowing end of the rod glows because of bioluminescent bacteria that live inside these creatures.

The fishing rod is a maneuverable spine, more or less. It’s used strategically to lure or bait its prey and/or mate. Cool right?


Interestingly, only the female anglerfish possess this fishing pole appendage.

The Male and Female Deep Sea Anglerfish

There is a significant difference between male and female deep-sea anglers. The most distinctive feature is the absence of the fishing rod on the male.

The male ceratioid lives solely to find and mate with a female.The male ceratioid is also significantly smaller, growing to a size of fewer than 2 inches. The males are generally black.

Believe it or not…

According to evolutionary biologist Theodore W. Pietsch of the University of Washington, mates are so scarce that it might be that only 1 percent of males ever find a partner for reproduction.


In a bizarre twist of evolutionary mystery, the digestive system of a male ceratioid ceases to work once it reaches sexual maturity. This means it can no longer feed independently. 

This is when things get really weird. Mating

Let’s take a closer look…

Over the course of an anglerfish’s lifetime, several males can physically fuse with a female to permanently join the pair.

The female produces pheromones and uses its luminescent lure to attract the male. When the male finds her, he attaches himself to her skin using small hook-shaped teeth.

Once he bites into her skin, the male then releases a chemical that fuses his lips to her skin. Over time, the blood vessels of the female connect to the male. From this point, he is part of her. The two are one…How romantic. Not!

Check out the bizarre process in this amazing video from National Geographic…

Video of a Ceratioid Mating Ritual

A Parasitic Yet Productive Relationship

The male will now live out his days connected to the female. He is nourished by all the female eats. In turn, the male can give her sperm whenever she needs it. No need to find another partner to give her sperm and fertilize the next generation.

It’s sort of a parasitic-like relationship. Although symbiotic might sound a little better, biologists have a name for it; sexual parasitism

It’s not monogamous, however. Females have been known to carry as many as six males at a time.

Crazy Right?

But that’s not all…


In a horror twist for the males, not only does he lose his digestive system, but also his eyes, his fins, and a few more now superfluous internal organs. The body parts the male no longer needs begin to atrophy.

In a sense, the male becomes nothing more than a sperm-producing appendage attached to the female. Mother nature has dished out a pretty raw deal to the hapless male ceratioid. Fancy finding love, only to become a parasitic sperm donor. Sad for the male angler fish isn’t it?

Anglerfish Babies

With a small colony of agreeable sperm bags attached to her body, the female has no shortage of fertilization available. Indeed, the moment she wants to spawn.

The female spawn her eggs in the form of a jello-like substance. This egg sheet can be 10 inches wide and up to 33 feet long. Once fertilized, the thin sheet of eggs floats freely in the ocean till hatching.

When the eggs hatch, the larvae head to the shallow surface where they’ll fatten up on plankton. As the larvae mature, they swim progressively deeper until they return to the oceanic zone from which they were spawned. 

The process starts again. The cycle of life. It is not known how long deep-sea anglers will live. It is speculated that they will mature in one to three years.

Let’s dig a little deeper

In their habitat, appropriate food may be tough to come by

So, the large teeth, large mouth, and belly allow them to stock up with one particularly large meal, instead of regular small ones.

Hunting Methods

A sleek and slimline fish like mackerel can run their prey down with sheer speed and brawn. Deep-sea anglers ain’t no mackerel. 

In fact, the shape of this species is far from conducive to the elegant, speedy maneuverability of so many of the ocean’s life forms.


The plump, ball-shaped anglers tend to kinda waddle awkwardly about the ocean, not swim. It’s not built for speed and grace. It’s built for deception and cunning.

How the Anglerfish Got Its Name

Deep-sea anglers use its fishing rod to dangle a glowing light directly in front of its large mouth. Its very similar to the design of the best fishing rods manufactured today, hence the name anglerfish. 

Underwater View
Underwater View

Prey is attracted to this glowing lure. When a squid or other fish, for example, comes to investigate the light, the deep sea anglerfish takes a shot, swallowing it whole should the prey size permit. Some have been known to swallow prey larger than themselves.

Many of you will remember the scene in Finding Nemo when Dory is attracted to the bright lure of the ceratioid. You will also remember she couldn’t see what lies behind the lure.

Just Waiting for the Right Time to Strike

At the depths where the deep-sea anglerfish lives, there is no light at all. They also have specially adapted skin that reflects blue light. 

To unsuspecting prey, deep-sea anglers are virtually invisible, except, of course, the light from the end of its fishing rod.

To unsuspecting prey, deep-sea anglers are virtually invisible, except, of course, the light from the end of its fishing rod. All they need to do is sit still and wait, fishing rod deployed and lights on.

Deep Sea Anglerfish Habitat and Distribution

Deep-sea anglerfishes live in the deep sea…funny that. They dwell in the open ocean at the lower depths of a zone called the Bathypelagic zone.

The Bathypelagic zone covers a depth in the water column from 3280 feet to 13,100 feet. To put that in some sort of perspective, the deepest part is nearly two and a half miles below the surface.

the deepest part is nearly two and a half miles below the surface…

The anglerfish’s broader family enjoys a global distribution. There are several species with isolated habitat, and there are those found all over the globe.

The deep-sea anglers are one member of the family that is found all over the world. Unless you have a super-high-tech submersible, you’re not likely to run into it, however.

Wanna Swim With the Deep Sea Anglerfish?

Swimming with deep-sea anglers is reserved for the select few. Even those lucky ones will require some very very serious equipment…

If this is one of your first choices for fish to swim with, maybe start with something a little more gentle, like the whale shark.

At the depths inhabited by the deep sea anglers, things are pretty inhospitable for all but the life adapted to it.

So what’s the problem?

Dangers Of Swimming with the Deep Sea Anglerfish

Firstly, there are near-freezing temperatures down there. Secondly, there is no light at all in these areas. It’s far too deep for the sun’s rays to penetrate.

Thirdly, and perhaps most troubling is the extreme water pressure at this depth. At the lowest depth of the Bathypelagic zone, the pressure is around 6000 pounds per square inch.

That’s enough pressure, or weight, to crush the concrete we drive our cars on. Let’s just say, you won’t be snorkeling at that depth any time soon…

No Room for Error

The submarine technology used to explore such depths isn’t new. However, the current technology is highly advanced, finely tuned and cutting edge. It’s extremely expensive, and dangerous. The slightest breach of the submersible at such depths is fatal to any occupant.

Not for everyone...

Deep Sea Anglerfish in Captivity

As you can imagine, fish that live at such depth and pressure are notoriously difficult to keep in captivity, let alone catch in the wild…

Some aquariums have specially designed and equipped tanks that simulate the ocean habitat at a depth of 3000 feet. They’re not your average living room fish tank.

Nothing Ordinary

Obviously, this presents problems. How do you feed and clean the tank? The answer is…with great difficulty, and very carefully.

You can’t just open a tank. When you feed them, food needs to be placed into a tube, taken to the appropriate pressure, then released into the tank. 

Here are two examples of deep-sea anglers in captivity. This picture is of a benthic, bottom-dwelling species. Watch this video of a deep sea anglerfish kept in a Japanese aquarium.

Video of an Anglerfish in Captivity

The Case of the Male Anglerfish

We don’t think the man has the stature or desire to be quite as bold as the female deep sea anglerfish, but then again, once attached to her, he doesn’t have to be.

One has to remember that they do spend part of their lives as eggs, larvae, and juveniles. Moreover, they do it in a zone far closer to the shallow surface. One can assume, they’d certainly be targets of other creatures while young and maturing.

The Human Threat to Deep Sea Anglerfish

Melanocetus johnsonii is not under threat. The International Union for Conservation of Nature (IUCN) has it listed as least concern (LC). 

Melanocetus johnsonii are somewhat protected owing to its habitat being at extreme depth. It’s not targeted commercially, and obviously out of reach of recreational anglers and tourists.

However, modern technology has increased the depths at which modern fishing boats can trawl. The potential remains that their populations could face serious pressure from trawling.

There is commercial interest for the tail meat of fish of the genus Lophius, known as monkfish or goosefish in fisheries found in western Europe, eastern United States, Africa, and East Asia.

It is widely used in cooking, and is often compared to lobster tail in taste and texture.

To make matters worse…

Unintended Consequences

There are many fish without commercial value that are threatened as a result of bycatch. The problem will only grow as the reach of fishing boats increase.

There needs to be a system in place to release accidentally caught fish, like what is being developed for the coelacanth and the ocean sunfish.

The threat of pollution is constant. Regardless of their depth, the entire oceanic environment could be thrown out of balance, with pollution, overfishing, and climate-related issues.

Wrapping Up The Deep Sea Anglerfish

Cute as a button? No. It doesn’t matter how hard you squint; deep-sea anglers will only ever look aesthetically compromised.

But beauty doesn’t always relate to cosmetic appeal. There’s something truly beautiful about this fish, and it’s not even the beauty from within.

Deep-sea anglers are a beautiful example of how evolution and mother nature have conspired to create a creature that is perfectly suited for its environment.

Efficient Design

From the female’s fishing rod appendage to its mouth, sharp teeth, and big belly. They’re designed to maximize the feeding opportunities of the deepest ocean.

While the poor old male ceratioid seems to have a pretty raw deal, the ‘mate or starve’ imperative bestowed by nature has ensured the continuation of the species in the toughest living conditions on earth.

While it’s not pretty, it no doubt inspires the curiosity of all those that look upon it. In terms of hopes for the future of our oceans, this can only be a good thing.

It might not be best-looking fish out there but it surely caught your interest. If you think your friends are as curious as you. Feel free to share the mystery with them too!

Thanks for reading the article. I hope you enjoyed it. You can click here if you want to be fascinated by another deep sea creature. Or click here if you want to learn more about catching hammerhead sharks. And don’t forget to check the site for an article or information you might need. Always remember, if it’s about fishing, we got it!

Image References

  1. Fish of the Abyss (Featured Image)
    By Todos los derechos reservados a su respectivo autor – National Geographic, CC BY-SA 4.0,
  2. Melanocetus Johnsonii By Ryan Somma – Flickr, CC BY 2.0,
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