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

Written by Sadie Dunlap
Published: January 21, 2022
Image Credit iStock.com/demarfa
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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. 

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.

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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.

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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.

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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.

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The Pacific Footballfish was discovered in 1985 by a  group of deep-sea fishermen. Since then, the creature was 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.

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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.

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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.

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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.

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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, crab, 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.

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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.

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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, spook fish, and even rabbit fish! 

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