25 Most Astonishing Sea Creatures

Posted by , Updated on June 22, 2024

The oceans are home to countless amazing sea creatures. **With** so much **biodiversity**, marine life **varies a lot** in looks, color, and size. Some are strange and **scary deep-sea** dwellers, while others are simply stunning. We’re focusing on the beautiful ones, covering some of the most remarkable marine life. From anemones and sea spiders to coral fish and sea stars, here is our handpicked list of the **25 Most Astonishing Sea Creatures**.



Mandarin Fish

Mandarin Fish Source: http://animaldiversity.org

Found in tropical waters of the western Pacific, the mandarin fish is a small, up to 6 cm (2.4 in) long coral fish famous for its unusual shape and beautiful, intense coloration.


Tube Anemone

Tube AnemoneSource: http://animal-world.com

Native to various locations within subtropical waters, the tube anemone comes in many different fluorescent hues and combinations of colors, which makes it a popular aquarium pet.


Flamingo Tongue Snail

Flamingo Tongue SnailSource: http://ocean.nationalgeographic.com

Common on many Caribbean and Atlantic coral reefs, the flamingo tongue snail is a strikingly colored mollusk that feeds on toxic sea fans. It incorporates the fans’ venom and becomes toxic itself.


Blue Tang

Blue TangSource: nature.org

One of over 70 species of surgeonfish, the blue tang lives in coastal waters, coral reefs and inshore rocky or grassy areas in waters from New York to Brazil and as far east as the remote Ascension Island. It is famous for the sharp spines on its tail, which are said to resemble surgeon’s scalpels.


Mantis Shrimp

Mantis ShrimpSource: aqua.org

Found in warm waters of the Indian and Pacific Oceans, the mantis shrimp is one of the most captivating and colorful creatures in the sea. These beautiful crustaceans have the most complex eyes in the animal kingdom, containing millions of light-sensitive cells.


French Angelfish

French AngelfishSource: http://raredelights.com

Native to the Western Atlantic Ocean as well as the Gulf of Mexico and the Caribbean, the French angelfish is an amazing tropical fish with dark coloration complemented by yellow stripes.


Leafy Sea Dragon

Leafy Sea DragonSource: seahorseworlds.com

Found in the tropical waters around Australia, the leafy sea dragon is one of the most unusual and fascinating sea creatures. Reaching up to 20 cm (8 in) in length, it is a unique species of the seahorse.


Sea Spider

Sea SpiderSource: emgn.com

Not related to the land spiders, the sea spiders are much simpler in form and function but are almost as common as their dry namesakes. These tiny marine arthropods can be found in most parts of the world.


Flower Hat Jelly

Flower Hat JellySource: Wikipedia

Although the flower hat jelly looks like a jellyfish, it actually belongs in the class Hydrozoa, while true jellyfish belong in class Scyphozoa. The flower hat jelly occurs in the West Pacific off southern Japan, and it delivers a painful sting.


Harlequin Crab

Harlequin Crab Source: whatsthatfish.com

Also known as the Brachyura crab or the swimmer crab, the harlequin crab is a stunningly colored true crab that occurs with sea anemones and tube anemones, close to shorelines of coral and rocky reefs.


Banggai Cardinal Fish

Banggai Cardinal FishSource: http://www.fishlore.com

The Banggai Cardinal Fish is a remarkable tropical fish with silver coloration and vertical black stripes. An endangered species, it is only found in a rather small area around the Banggai Island in Indonesia.


Spotted Eagle Ray

spotted eagle raySource: oceana.org

Reaching widths of over 3 m (almost 11 ft), the spotted eagle ray is one of the largest eagle rays, with only the mantas growing bigger. It is an active swimmer and predator known to eat invertebrates and small fish.


Clown Anemonefish

Clown AnemonefishSource: http://animals.nationalgeographic.com

Bright orange with 3 distinctive white bars, clown anemonefish are among the most recognizable and popular of all reef-dwellers. They reach about 11 cm (4.3 in) in length and are named for the multicolored sea anemone in which they make their homes.


Harlequin Shrimp

Harlequin Shrimp Source: http://www.liveaquaria.com

A popular aquarium pet, the harlequin shrimp is a beautifully colored shrimp found in the tropical waters of the Indian and Pacific Ocean. It has a white body with large light blue spots. The males are slightly smaller than the females.


Blue Dragon

Blue DragonSource: Pelagic snails: the biology of holoplanktonic gastropod mollusks via Wikipedia

Also known as the blue glaucus and the blue sea slug, the blue dragon is a species of small, blue sea slug. Measuring just up to 3 cm (1.2 in) in length, this curious animal occurs throughout the world’s oceans, in temperate and tropical waters.


Discus Fish

Discus FishSource: fishlore.com

Native to the Amazon river basin in South America, the discus fish is one of the world’s most beautiful tropical fish. Due to its distinctive shape and striking coloration, the discus is a popular aquarium pet; it is sometimes even referred to as the “king of the aquarium.”


Venus Flytrap Sea Anemone

Venus Flytrap Sea Anemone Source: emgn.com

Named after its plant namesake because of its physical and feeding mechanism similarities, the Venus flytrap sea anemone is a large, deep-sea anemone that feeds by trapping food in its “mouth” structure as its prey enters the trap.


Royal Starfish

Julie Worthy starfishSource: "Astropecten Articulatus“ via Wikipedia

One of the most remarkable starfish, the royal starfish is a sea star that lives most commonly at the mid continental shelf around 20–30 m (70–100 ft) in the Western Atlantic. It is a carnivore and feeds on mollusks, which it catches with its arms and then takes to the mouth. Photo used with permission: Julie Worthy Photography (facebook)


Berghia Coerulescens

Berghia coerulescens Source: “Berghia Coerulescens” via Wikipedia, image: https://commons.wikimedia.org (public domain via photographer)

Berghia Coerulescens is a species of sea slug that can be found in the Central and Western Mediterranean and the Northern Atlantic Ocean. This stunningly colorful creature reaches up to 7 cm (2.8 in) in length.


Red Lionfish

Red LionfishSource: nationalgeographic.com

One of the most iconic tropical fish, the Red Lionfish is native to the reefs and rocky crevices of the Indo-Pacific, although it has found its way to warm ocean habitats worldwide. They are popular in some parts of the world as food but are far more prized in the aquarium trade.


Short-Snouted Seahorse

Short-Snouted SeahorseSource: "Rare seahorses breeding in Thames" via Wikipedia

Endemic to the Mediterranean Sea and parts of the North Atlantic, the short-snouted seahorse is a mid-sized, up to 13 cm (5.1 in) tall seahorse that inhabits shallow muddy waters, estuaries or seagrass beds.


Lagoon Triggerfish

Lagoon TriggerfishSource: “The American Heritage Dictionary of the English Language: Fourth Edition” via Wikipedia, image: https://commons.wikimedia.org (public domain)

Also known as the blackbar triggerfish or the Picasso triggerfish, the lagoon triggerfish is a remarkable tropical fish found on reefs in the Indo-Pacific region. It often occurs in Hawaii where it is called “humuhumunukunukuapuaa.”


Green Sea Turtle

Green Sea TurtleSource: animals.nationalgeographic.com

Inhabiting tropical and subtropical coastal waters around the world, the green turtle is a large, weighty sea turtle with a wide, smooth carapace. Weighing up to 320 kg (over 700 lb), the green turtle is among the largest sea turtles in the world.


Phyllidia Babai

Phyllidia BabaiSource: “Phyllidia Babai“ via Wikipedia

A species of sea slug, Phyllidia Babai is a colorful marine nudibranch that has been reported from several locations in the Pacific Ocean such Papua New Guinea, South Korea, and Australia.


Crown-of-Thorn Starfish

Crown-of-Thorn StarfishSource: gbrmpa.gov.au

The crown-of-thorns starfish is a coral-eating starfish native to the Indo-Pacific region. Despite its beautiful appearance, this species is often considered a pest as outbreaks of this creature pose significant threats to coral reefs, particularly the Great Barrier Reef.