10 Deep Sea Creatures: Discover the Rarest Scariest Animals Beneath the Seas!

Written by Sadie Dunlap
Updated: November 18, 2023
Share on:

Advertisement


There’s no doubt that deep-sea creatures are the stuff of nightmares. The truth is, though, that these astounding creatures are widely misunderstood. For example, many of the terrifying features that make these animals look so terrifying are essential to their survival. 

Take your pick – all of these deep dwellers are scary!

Let’s dive in to learn more about the top ten most rare and scary animals in the deep blue sea! 

#1 Barreleye Fish (Macropinna microstoma)

deep sea creatures barreleye fish

Barreleye fish have a fluid-filled protective sack over their eyes.

©iStock.com/3dsam79

The Barreleye fish, also known as the spook fish, is a deep-sea dweller with an astounding adaptation to see in near pitch-black waters. The entire top portion of their heads is completely transparent. Encased within are two glowing green eyes that are pointed above their heads. 

The Barreleye fish lives anywhere from 2,000 to 2,600 feet under the sea. They feast on small crustaceans and other small organisms that get trapped in the tentacles of siphonophores. Scientists say that the transparent layer of tissue that covers their heads helps to protect their eyes from getting stung by the siphonophores they steal their food from.

At first glance, it appears that this fish’s eyes are permanently locked into an upward-gazing position. Researchers thought this was the case until 2019 when it was discovered that the Barreleye can rotate its eyes. 

#2 Tardigrade (Tardigrada)

tardigrade deep sea creatures

Tardigrades are also called water bears or moss piglets.

©iStock.com/fruttipics

Tardigrades, also known as water bears or moss piglets, are nearly microscopic organisms that can live in ocean depths up to 15,000 meters below the surface. They are arthropods that have eight legs and puffy bodies that resemble the caterpillar from Alice in Wonderland. 

Tardigrades are astoundingly resilient and can survive conditions that would kill most other forms of life. In extreme conditions, they can transform into a dehydrated ball, called a tun, to preserve themselves. Researchers say that tuns are proven to be able to survive extremes of 300 degrees F and minus 328 degrees F. They can also withstand six times the amount of pressure present at the ocean floor. 

These deep-sea creatures have no bones in their minuscule bodies. Their bodies are instead made up of fluid-filled compartments called hemolyphs. This fluid is full of nutrients that nourish their body.

#3 Sea Spider (Pantopoda)

sea spider image

Sea spiders live at depths of up to 2,300 feet under the ocean.

©simone tognon/Shutterstock.com

If you’ve ever been spooked by an average garden spider, you wouldn’t want to come face-to-face with a sea spider. Sea spiders creep along the ocean floor and can grow to be up to three feet wide. For reference, that’s about the same length as two average house cats (sans tails) combined.

Sea spiders have been found at depths up to 2,300 feet under the sea. These deep-sea creatures are present in all oceans across the globe and feed on slow-moving animals on the ocean floor such as sea nettles and sponges. Some species have claws that assist them in capturing their prey.

Even though sea spiders look similar to land arachnids, they are not the same creatures. Land spiders are part of the Arachnida class. Sea spiders, on the other hand, are in the Pycnogonida class. However, they do have some similarities, as well. For example, they are both considered arthropods and belong to the subphylum Chelicerata.

#4 Pacific Footballfish (Himantolophus sagamius)

deep sea creatures pacific footballfish

Pacific Footballfish were discovered in 1985.

©Jules_88/Shutterstock.com

The Pacific Footballfish was discovered in 1985 by a  group of deep-sea fishermen. Since then, the creature has been classified with other deep-sea creatures called anglerfish. To date, there are over 300 different species of anglerfish identified. 

The Pacific Footballfish became one of the most well-known deep-sea creatures in the world following the release of Finding Nemo. The first dorsal fin along its back extends forward and is bioluminescent, which means that it emits its own light. This tiny light is used to lure the fish’s prey. 

This terrifying animal lives at depths from 2,000 to 3,300 feet deep, where both light and food are hard to come by. Consequently, Pacific Football fish will eat anything that it comes across. Some of its most common meals include crustaceans and squids. 

Even though the Pacific Footballfish might not look friendly, it is not a dangerous fish. 

#5 Frilled Shark (Chlamydoselachus anguineus)

frilled shark picture

The Frilled Shark swims with a wide-open mouth to catch unsuspecting prey.

©iStock.com/3dsam79

With an eel-like body and snakelike head, the Frilled Shark is the stuff of nightmares. Its needle-like teeth are spaced far apart and have three cusps. This terrifying deep sea creature lives far beneath the surface of the ocean, as deep as 4,921 feet deep.

The Frilled Shark swims through the dark ocean with its mouth wide open. While this might make the animal look more terrifying, researchers think they do this to attract prey. This frightening creature eats a diet almost completely composed of squid. However, they will occasionally eat smaller sharks and fish.

The Frilled Shark is one of the most primitive species of shark under the sea. Scientists say that they have been around for millions of years. Additionally, research shows that they haven’t changed much over the course of that time. 

#6 Viperfish (Chauliodus sloani)

deep sea creatures viperfish

The Viperfish are extremely rare, so scientists don’t know much about them.

©superjoseph/Shutterstock.com

Perhaps one of the most well-known deep sea creatures is the Viperfish. This carnivorous sea creature is among the most dangerous predators in the deep sea. They have thin, elongated bodies and large, pointy teeth that help them capture prey in the darkness of the deep sea. 

During the day, Viperfish dive deep into the ocean and can be found at depths as deep as 5,000 feet. However, food is scarce at this depth. Consequently, they swim to shallower depths of around 2,000 feet at night, where more sea creatures can be made into their dinner. 

Because of their deep-sea homes, scientists know very little about the Viperfish. They are thought to be external spawns, which means that females release eggs into the water to be fertilized. What little is known about the species is mostly collected by scientists after unsuspecting deep-sea fishermen catch one.

#7 Fangtooth Fish (Anoplogaster cornuta)

fangtooth fish closeup

The Fangtooth Fish survives on a diet of fish, squid, and crustaceans.

©iStock.com/demarfa

As their name suggests, Fangtooth Fish are among the deep-sea creatures with a mouthful of sharp, fang-like teeth. These terrifying creatures are carnivorous deep-sea creatures that live at depths of over 16,000 feet. However, they have been known to swim to the surface to capture prey. 

Many deep-sea creatures conserve their energy by waiting for prey to come to them. However, Fangtooth Fish are active predators who seek out their meals. Their enlarged, sharp teeth help ensure that they are able to capture whatever comes their way. 

These fish prefer a diet of squid, fish, and crustaceans. They don’t have any glowing organs or other eye-catching features, so instead rely on their sense of smell and sound to seek out their prey.

There’s no doubt that the common Fangtooth has a strikingly fearsome appearance. However, scientists say they are wholly harmless to humans since they only measure around 7 inches long when fully grown. 

#8 Giant Isopod (Bathynomus giganteus)

deep sea creatures giant isopod

The Giant Isopod is closely related to land-dwelling pillbugs.

©kikujungboy CC/Shutterstock.com

Have you ever captured a roly-poly or pillbug in the summertime? Imagine a giant version of that tiny critter, except it lives at extreme depths on the ocean floor. Believe it or not, these creatures are real, and they’re called Giant Isopods, who are closely related to the land critters.

Giant Isopods are deep-sea creatures that scavenge the ocean floor for prey. They are carnivorous animals that have a diet of squid, fish, crabs, sea sponges, and more. Since food is scarce at the bottom of the ocean, Giant Isopods have evolved to go long periods without food – in some cases, as long as four years! 

When they’re frightened, Giant Isopods can roll up into a ball.  This protects their inner organs and is made possible due to the absence of a spine. Their tough exterior shell protects them from outside threats. When they’re not hunting, they can be found buried beneath ocean sediment on the ocean floor, which allows them to preserve their energy. 

#9 Japanese Spider Crab (Macrocheira kaempferi)

japanese spider crab deep sea creatures

Japanese Spider Crabs will eat almost anything that crosses their paths.

©LELACHANOK/Shutterstock.com

It probably doesn’t come as much of a surprise that Japanese Spider Crabs are crustaceans found in the waters surrounding Japan. Researchers say that this species is the largest arthropod known to man and can live to be one hundred years old or more. 

Japanese Spider Crabs are creatures of opportunity. This means they will feed on almost any animal that comes their way. They are also omnivorous, which means they also eat plants. They capture prey by camouflaging themselves with algae and other sea matter. This allows them to catch unsuspecting animals with ease.

#10 Chimaera (Chimaera monstrosa)

chimaera side profile

Chimaera

don’t have any bones and instead have cartilage to support their frames.

©Vladimir Wrangel/Shutterstock.com

At depths of around 4,200 feet in the ocean lives the Chimaera. These deep-sea creatures don’t have any bones in their body. Instead, their inner structures are made of soft, spongy cartilage. 

On each side of their head, Chimaeras have what appear to be eye sockets. However, these menacing-looking animals don’t have eyes. Instead, these are sensory pads that are used to detect electrical fields in the water. This allows the creatures to “see” in the dark, murky depths that they call home.

Chimaeras are also known as ghost sharks, ratfish, spookfish, and even rabbitfish! 

Summary of the 10 Rarest and Scariest Deep Sea Creatures

RankCreatureWhat Makes Them Interesting
1Barreleye FishThe entire top portion of their heads is completely transparent. Encased within are two glowing green eyes that are pointed above their heads. 
2TardigradeResearchers say that tuns are proven to be able to survive extremes of 300 degrees F and minus 328 degrees F.
3Sea SpiderSea spiders creep along the ocean floor and can grow to be up to three feet wide.
4Pacific FootballfishThe first dorsal fin along its back extends forward and is bioluminescent, which means that it emits its own light. This tiny light is used to lure the fish’s prey. 
5Frilled SharkIts needle-like teeth are spaced far apart and have three cusps, and they swim with their mouths wide open.
6ViperfishThese are among the most dangerous predators in the deep sea.
7Fangtooth FishThese terrifying creatures are carnivorous deep-sea creatures that live at depths of over 16,000 feet.
8Giant IsopodThey have evolved to go long periods without food – in some cases, as long as four years! 
9Japanese Spider CrabThe largest arthropod known to man and can live to be one hundred years old or more. 
10ChimaeraThese deep-sea creatures don’t have any bones in their body. Instead, their inner structures are made of soft, spongy cartilage.

Honorable Mention: Other Deep Sea Animals

A sea cucumber (Scotoplanes globosa) appearing to "shelter" the crab (family Lithodidae), taken from MBARI's ROV "Doc Ricketts" aboard the R/V Western Flyer at a depth of approximately 1260 meters on March 9, 2010.

The sea pig is a genus of deep-sea cucumber that can be found at depths of 1232 meters.

©NOAA/MBARI, CC BY-SA 3.0 – License

The deep sea has fascinated both scientists and marine enthusiasts for quite some time. It is believed that there may be many undiscovered creatures that dwell in the deep, some residing too far to be unearthed. This doesn’t stop expeditions from attempting to locate both new and yet-to-be-detected beings. Take a look at just some of the fascinating specimens that deserve recognition:

  • Blobfish (Psychrolutes phrictus)- there are over 35 recognized species in the family Psychrolutidae, of which this bottom-dwelling marine sculpin is part. Found mainly in the Atlantic, Indian, and Pacific Oceans, where they dwell along continental shelves, in cold habitats between 840 and 3,940 feet deep, these interesting-looking fish feed mainly on crustaceans, mollusks, and sea pens.
  • Sea pig (Scotoplanes) – belonging to the family Elpidiidae, sea pigs are a genus of deep-sea cucumbers that can be found at depths of over 1200 meters (over 3,900 feet). These sea cucumbers have large tubular appendages, thought of as feet, that appear leg-like and their movement is caused by the use of water cavities within their skin. They are typically found in the abysmal plains of the Atlantic, Indian, and Pacific Oceans, and are one of the most abundant animals found in this region.
  • Angler fish (Ceratias holboelli) – belonging to the family Ceratiidae, which consists of more than 200 species of deep-dwelling animals, these fish can be found throughout the world. Depending on the species, which can also be referred to as sea devils, they can be found on continental shelves and depths of 400 and 2,000 meters (1,300 and 6,600 feet).

The photo featured at the top of this post is © iStock.com/demarfa


Share on:

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.