22 Scary Facts About The Viperfish

The deep sea is full of scary-looking predators, and they’re not always huge in size.

Some of the smaller ones are just as scary and ferocious. In this post, you’ll discover the ultimate list of facts about the viperfish, one of those small monsters of the ocean.

Related: The viperfish is included in our list of creepy animals in the ocean. You’ll see that there are plenty of other monsters around as well.

1. They live in deep water

Are you getting a bit worried to take a swim in the ocean because of a newly developed fear of encountering a viperfish?

You don’t have to worry too much about that because the chances of you ever coming across one of these monsters is non-existent.

Viperfish live at depths of 250 – 5000 feet (80 – 1,520 meters). They stay very deep in the daytime and come to shallower depths to hunt at night.

2. They live in tropical waters

But this doesn’t necessarily mean that they enjoy the warm water. Where they usually hang out, at depths of over 3000 feet (1000+ meters), the average temperature of the water is just 4 degrees Celsius.

3. Do you think they look scary?

It’s fair to assume that just about everybody does!

What’s most striking about viperfish is their large mouth and needle-like teeth. This in combination with a hinged jaw makes gives this type of fish a particularly creepy appearance.

facts about the viperfish
The viperfish has a scary appearance that could probably give you nightmares / Source

4. They aren’t that big

Even though the viperfish has a creepy appearance, these are relatively small fish. The average adult viperfish is only about 30-60 centimeters (12 – 23.5 in) long.

This isn’t nearly as big as some other monsters of the deep sea such as the Goblin Shark, which can grow over 3 meters (10 feet) long.

5. What’s the scientific name of the viperfish?

The scientific name of the viperfish, which means all members of the genus, are referred to as “Chauliodus.”

6. How many members in the genus Chauliodus are there?

There are a total of 9 extant members in the genus Chauliolous and 2 extinct members.

The 9 extant members are:

  • Chauliodus Barbatus
  • Chauliodus Danae
  • Chauliodus Dentatus
  • Chauliodus Macouni (pacific viperfish)
  • Chauliodus Minimus
  • Chauliodus Pammelas 
  • Chauliodus Schmidti
  • Chauliodus Sloani (Sloane’s viperfish)
  • Chauliodus vasnetzovi

The 2 known existing members, which date from the Late Miocene (11.63 to 5.333 million years ago) are:

  • Chauliodus Eximus
  • Chauliodus Testa

7. They come in multiple colors

There have been multiple viperfish found and they don’t have a uniform color. They can be green, silver, or even black.

8. They evolved to become more black

Viperfish, along with multiple other species living in the near-dark depths of the ocean, are becoming more and more black. Scientists Sönke Johnsen and Karen Osborn from Duke University have discovered that these fish are adapting to their habitat to become invisible to prey.

Complex nanostructures in the fish’s skin can filter nearly all incoming light, effectively making them “disappear.”

Marine biologist Johnson mentions that “when you look at them, it’s just like a hole in the universe.”

Pretty astounding!

Viperfish black
Viperfish can become invisible to prey / Source

9. They use a trick to lure their prey

If you’re completely black and you float around without moving, it might be complicated to get close enough to your unsuspecting prey.

The viperfish uses a trick to solve this problem as well, as they possess light-producing organs called photophores at the sides of their bodies.

By flashing this light on and off, they can draw the attention of the unlucky creatures that naively follow this light. The moment they come within range of one of the most ferocious predators of the deep sea, they get devoured.

10. That’s not all this organ is used for

If you can barely see things, then using light signals is pretty much the only way to communicate properly.

The light-producing photophores are therefore also used as a means of communication for the viperfish.

11. They can see in color

One of the most interesting facts about the viperfish is something that scientists recently discovered, which is the fact that they can see in color.

Just as humans, viperfish appear to be using two types of photoreceptor cells called rods and cones to see. Both cones and rods contain light-sensitive proteins called opsins.

Most vertebrates, however, only have one opsin protein which means they become color-blind in dim light such as the deep ocean.

Amazingly, the viperfish has adapted to dark conditions and developed additional proteins, allowing them to see in color in their natural habitat.

This can indeed make the difference between life and death in these extremely harsh conditions!

viperfish can see in color
The viperfish can see in color / Citron / https://creativecommons.org/licenses/by-sa/3.0/deed.en

12. What does a viperfish eat?

Just like any other deep-sea fish, viperfish can spend a long period of time without food. When it comes to what they eat, it doesn’t seem that they are very picky at all, which makes sense when food is scarce.

They mostly eat smaller fish such as lanternfish and bristlemouths, but a variety of other small fish species has been found in the stomach of captured viperfish.

13. We wouldn’t want to be their prey

The best part about being their prey (is there a good part really?) is that it’s most probably over quickly. From what we know, one moment the small unfortunate fish thinks there’s a party with flashing lights going on somewhere, and the other moment it’s sliced to bits by the need-like teeth of the viperfish.

Regardless, we give all small fish in the deep sea the advice of avoiding techno or rave parties at all costs. There are none and believing otherwise will get you killed!

14. They can swallow their prey whole

Viperfish don’t have the habit of chewing their food properly. In fact, they simply swallow whatever they eat whole.

The first vertebra behind their neck serves as a shock absorber which can rotate to allow their meal to pass.

Viperfish head and teeth / Wiki Commons

15. They have stretchable stomachs

Because they can swallow their prey whole, they need to somehow be able to digest their food.

The one thing they need for this is a stretchable stomach that can stretch to double its original size.

16. How long do viperfish live?

In the wild, the viperfish has a remarkably long lifespan as they can live between 30 and 40 years.

In captivity, (mostly accidentally as only scientists would be interested in actually catching one to study them) they only live a few hours.

It’s really hard to replicate the conditions of the deep ocean so most captured animals don’t live long, even if the replicated conditions appear to be perfect. One example is the capture of a goblin shark that died a few days later in a perfectly optimized aquarium in Japan.

17. They aren’t covered in scales

Even though it appears that they are covered in scales, they actually aren’t. They are covered with a thick, transparent coating containing microscopic spheres.

Up until today, we really don’t know what this coating is made of as this gelatinous layer doesn’t appear to be merely a slime secretion.

facts about the viperfish
The viperfish has a gelatinous coating of unknown substances / Source

18. They can swim pretty fast

For them to be able to get food in their stomach, they need to be able to attack their prey fast enough and outswim it.

Scientists believe they can swim at a speed of two body lengths per second. Because this has only been observed a few times as it’s hard to keep them alive in captivity, this isn’t an official number.

19. There’s another reason they need to be able to swim fast

The deep ocean is a harsh and ruthless world. Apart from having to find your own food using all the tricks available to you as a species, you constantly need to be on the lookout for predators or you get eaten alive yourself.

This also applies to the viperfish, which have more than one predator to fear such as all types of species of sharks and even dolphins.

Kill or be killed every day, it’s pretty tough to be a viperfish!

20. How does the viperfish reproduce?

Because the viperfish live in a place that isn’t accessible to humans, and they can’t be kept alive in captivity long enough, it’s really hard to fully study and understand their behavior.

It’s commonly believed though that they are external spawners, which means the females release eggs to be fertilized.

The young larvae most probably get born in January and march and only measure about 6 millimeters at birth, which is less than a quarter of an inch!

21. They move up and down

One pattern that has been discovered is the fact that they move up and down the ocean every day. In the daytime, they can be found very deep, and they move higher in the night to try and find a meal.

This pattern is referred to as vertical migration.

22. They hold a world record

The viperfish is actually listed in the Guinness Book of World Records!

What are they in it for?

Well, it’s nothing something they should be too proud of. They are in the book because they are the fish with the largest teeth relative to head size.


head of the viperfish
The head and teeth of the viperfish / Wiki Commons

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