Deep-sea creatures are easily the most bizarre and scary-looking marine creatures. But they are also some of the most fascinating. They have developed special adaptations in order to survive on tiny food supplies and in extreme pressure. Let’s discover a world without sunlight—the world of bioluminescence—with these ten incredible deep sea fish.
Anglerfish
Found at depths of: Over 6,500 feet (2,000 meters)
Typical characteristics: Fishing pole-like dorsal spine with a light at its end protruding from the middle of the fish’s head
The Anglerfish is arguably the most famous deep sea fish and is often depicted in deep ocean movies and documentaries. There are more than 200 species of Anglerfish, many of which live in the midnight zone (3,300 – 13,100 feet, or 1,000 – 4,000 meters deep) in the cold waters of the Atlantic and Antarctic oceans.
The light-organ protruding on a stalk from the fish’s head is tipped with esca — a sac of bioluminescent bacteria — that gives the Anglerfish’s bioluminescent lure its characteristic glow. However, only females actually have this distinctive light.
Female Anglerfish are ambush predators that can grow up to 4 feet (1.2 meters). They use the bioluminescent light on their head to lure in any potential prey and also to attract mates. Males are incredibly smaller than their female counterparts reaching only 8 inches (20 centimeters). In some cases, these small fishes latch onto females and eventually fuse with them to obtain nutrients from their bloodstream.
Stoplight Loosejaw
Found at depths of: Around 1,600 to 13,100 feet (500 to 4,000 meters)
Typical characteristics: The distinguishing feature of the Stoplight Loosejaw is that its jaw is larger than its skull and has no floor
The Stoplight Loosejaw belongs to the family Stomiidae, better known as dragonfish. It has an elongated body and rounded snout with sharp fangs, which give it its “dragonlike” appearance. The jaw of this ambush predator hangs loose, ready to quickly snap and catch even larger prey whenever the opportunity arises.
Most deep sea creatures produce blue light, but Loosejaws can both see and produce red light, which gives them a significant advantage over other fish living in the twilight (mesopelagic) and midnight (bathypelagic) zones. It allows them to stay hidden when using the red light to look for prey. This is because the long wavelength red light is invisible to most other deep sea fish. Loosejaws are actually able to produce both red and green light thanks to bioluminescent organs (photophores) around their eyes — this earned them their name “stoplight.”
Chimaera
Found at depths of: Maximum 8,500 feet (2,600 meters), but usually spotted around a depth of 1,600 feet (500 meters)
Typical characteristics: Tapering body and bulky head with a one gill opening
Chimaeras are also known as “rabbitfish” because of their big eyes and prominent snout, and “ratfish” because of their whip-like tail, as well as “ghost sharks“. They are closely related to sharks, rays, and skates. They can be found in all oceans, with the exception of the Arctic and the Antarctic, at great depths of up to 8,500 feet (2,600 meters) in the midnight zone. Despite being regularly caught as bycatch in mixed fisheries, researhers still do not know very much about these species.
Just like their relatives, they have skeletons that are entirely made of cartilage rather than bone like other deep sea fish. Other similarities with sharks are their smooth, scaleless skin and the electrosensory organs Chimaeras use to detect their prey.
Mariana Snailfish
Found at depths of: 22,600 feet (6,900 meters) to 26,830 feet (8,178 meters)
Typical characteristics: Short rounded body with a long tail and translucent scaleless skin
Mariana Snailfish holds the record for the deepest fish caught (in situ) from the ocean floor. It was collected in the Mariana Trench at a geat depths of 26,135 feet (7,966 meters), but since then, it has been filmed at even greater depths. It’s physical appearance resembles a fleshy tadpole that is scaleless and colorless with cartilage instead of bone.
In order to survive so deep, the Snailfish needs to be able to withstand approximately 800 times greater pressure than the pressure at sea level. It is a top predator and feeds on invertebrates, such as tiny crustaceans.
Lanternfish
Found at depths of: Up to 3,300 feet (1,000 meters)
Typical characteristics: A small elongated fish with large eyes can have photophores producing a blue-green light line over the body, typically on its belly, face, and tail
Lanternfish most likely use their bioluminescence for communication and counterillumination (a form of camouflage). They undergo vertical migration, which means they move closer to the ocean surface—the epipelagic zone (10-100m or 30-300 ft.)—during the night in order to feed on their primary food source, zooplankton.
With over 240 species, Lanternfish range in body size anywhere from 0.7 to 12 inches (2 to 30 cm). This interesting fish can be found throughout the world’s oceans. In fact, according to research, Lanternfish make up 60% percent of deep sea fish populations. This makes them essential for the marine ecosystem and leads to them becoming important prey for many larger marine animals such as other deep sea fish, tuna, salmon, jumbo squid, whales, dolphins, sharks, and others. Lanternfish are also a common target of commercial fishing.
Viperfish
Found at depths of: 660 – 3,300 feet (200-1,000 meters) in the twilight zone but can be found deeper than that
Typical characteristics: The Viperfish has two very long front fangs that stick out of the mouth and run past its eyes
Like some other deep sea fish, Viperfish also migrate during the night to shallower waters where they feed. They typically don’t get bigger than 1 foot (31 centimeters), so they hunt small crustaceans or fishes, such as Lanternfish. They have long, sharp teeth and protruding lower jaw, which earned them their name.
Viperfish use their bioluminescence in an interesting way. Not only do they use it to attract prey, but they also use the glowing photophores along their bellies for counterillumination. This allows them to match their background better and hide their silhouette from predators lurking below them.
Rattail Fish
Found at depths of: 650 to around 23,000 feet (200 – 7,000m)
Typical characteristics: Large eyes, longer pelvic fins, and a long tapering tail
There are hundreds of species of Fattail fishes, otherwise called Grenadier. Grenadiers are benthic fish, which means they live near the ocean floor. The depth record for Rattail fish is 23,005 feet (7,012 meters).
While some species are known as apex predators, others are scavengers. Rattail fishes eat a large variety of food, including squid, small crustaceans and other deep sea fish.
They have a really strong sense of smell and touch. Unfortunately for Grenadiers, they are one of the deep sea fish that often gets caught with trawl nets. This is dangerous for their habitat and their numbers, as they reproduce quite slowly.
Owlfish
Found at depths of: 1,800 to 22,000 feet (550 to 6,600 meters)
Typical characteristics: Owlfish have large owl-like eyes and can be dark brown to black in color
There’s little we know about the Owlfish. It is named for its large eyes resembling an owl, and it can be found in the North Pacific. The Owlfish needs to take full advantage of the size of its eyes in order to see prey in the bathypelagic zone it lives in. Owlfishes are known to feed mainly on a variety of small shrimp and jellyfish.
Coelacanth
Found at depths of: 500 to 800 feet (150 to 240 meters)
Typical characteristics: Paired lobe fins that resemble limbs and hard scales
The Coelacanth is often referred to as the “living fossil.” Found in Indonesia, this specimen was believed to have died out together with dinosaurs until one was caught near the coast of Africa. The Coelacanth is the largest fish on this list. It can grow over 6.5 feet (2 meters).
Latimerias are foraging predators that feed on almost anything they can find. Scientists think that Coelacanths have an electric sense that helps them locate prey. From what we know, they live in deep water caves or rocky reefs of the western part of the Indian Ocean along the east African coast as well as the Indonesian waters near Sulawesi.
Deep Sea Lizardfish
Found at depths of: 2,000 to around 11,500 feet (600 to 3,500 meters), but most commonly found in depths between 3,200 and 7,000 feet (1,000-2,000 meters)
Characteristics: Flat lizard-like head that is slightly raised and a large mouth with multiple rows of sharp teeth
The Deep Sea Lizardfish might resemble its relative Shallow-Water Lizardfish but is, in fact, one of the top predators of the midnight zone. This deep-sea fish species is an ambush predator that lives on the sea floor. It is not picky; it eats basically anything that passes by, even its own kind.
These deep sea fish are hermaphrodites, meaning it has both male and female reproductive organs. They have been spotted mainly throughout the Atlantic and Pacific oceans.
Frilled Shark
Found at depths of: 400 to around 4,200 feet (120 to 1,280 meters)
Characteristics: Frilly gill slits, eel-like body and trident-shaped teeth
The Frilled Shark resembles something out of prehistoric times. With its elongated body and fins positioned far back, it moves through the water column much like eels, with a sinuous, serpentine swimming style. Its most distinctive feature, the frilly gill slits that give it its name, add to its unusual appearance.
This deep-sea predator has a diet primarily consisting of squid, which it captures with its specialized, trident-shaped teeth. Although rarely encountered and therefore poorly understood, scientists have gleaned some insights from captured individuals. Frilled sharks are ovoviviparous, meaning the young develop inside eggs within the mother’s body, nourished by yolk sacs, and are born live.
Ocean Insights: Hear From Our Experts
By Dr. Rabiah Ryklief
Principal Scientist and Lecturer of Marine Science, with a PhD in Zoology
Deep-sea mining presents a significant threat to biodiversity conservation in the face of climate change. The deep sea, a largely unexplored and vital ecosystem, is home to a diversity of species, many of which are still unknown to science. Mining activities, such as the extraction of polymetallic nodules (containing critical metals), risk causing irreversible damage to these fragile ecosystems through habitat destruction, sediment plumes, and noise pollution.
This biodiversity loss could have cascading effects on the ocean's ability to sequester carbon and regulate the climate. Moreover, deep-sea mining itself is energy-intensive, contributing to greenhouse gas emissions, and could disrupt the ocean floor's capacity to store carbon, potentially exacerbating the climate crisis. As climate change already puts immense pressure on marine life, deep-sea mining adds another layer of stress, jeopardizing the health and resilience of this critical ecosystem.
FAQs
How do deep-sea fish survive the pressure?
Most deep-sea fish do not have air pockets in their bodies, meaning the pressure doesn’t affect them the same as shallow-water fish. They also have a chemical called TMAO, which protects some vital proteins and molecules in their bodies from compression.
What is the deepest living deep sea fish?
The Mariana snailfish was caught at 7,966 m (26,135 ft) depth in the Mariana Trench but has been filmed in even greater depths. Mariana snailfish holds the record for the deepest fish caught in situ from the bottom of the ocean.
Why are Giant Isopods so big?
Deep-sea gigantism might be an adaptation to the intense pressure or scarce food resources, allowing the Giant Isopod to store fat and survive for years without eating. The relative lack of predators in the deep ocean also allows them to grow larger without as much risk. Additionally, their increased size may aid in oxygen absorption, crucial for survival in the deep.
Do any fish live in the Challenger Deep?
While there are no fish known to live as deep as the bottom of Challenger Deep (about 36,000 feet below sea level), there are plenty of fish and other marine animals living in slightly shallower parts of the Marianna Trench. However, there are some organisms, such as marine microorganisms, shrimp, or sea cucumbers, that live in the Challenger Deep.
What are Sea Pigs?
Sea pigs are a type of sea cucumber that get their name from their pink color and their diet, which includes sifting through the mud for dead animals. They use their stilt-like tube feet to move around and lift themselves above the soft sediment in deep waters.
