10 Stunning Underwater Plants and Sea Creatures on the Ocean Floor

White-Plumed Anemone

With more than 1,200 species of sea anemone in the ocean, these creatures are responsible for some of the most stunning colors and shapes you'll find underwater. The white-plumed anemone is among the most captivating because of its odd cauliflower floret-esque appearance.

This columnal plant can grow as tall as three feet and thrives in cold water from Alaska to San Diego. And while the soft pouf at the top looks like a nice place for a fish nap, those tentacles are the anemone's primary tool for stinging and catching prey.

Red Sea Whip

The red sea whip is what you might expect a crimson-headed cartoon character's hair to look like if they were upside down, This soft coral belongs to the order Alcyonacea and the family Ellisellidae. Soft corals do not have the calcium carbonate skeletons found in hard corals, so their malleable tentacles dance with the water. Each branch of the sea whip contains countless coral polyps (small tubes fringed with tentacles) that gather food.

Located primarily in shallow waters in the tropics and subtropics, these coral are found across the world. Like the red whip, corals of this family are usually brightly colored and come in different shapes.

Green Sea Anemone

This vibrant green sea anemone bears a strong resemblance to the land-based Anastasia flower, a type of spider chrysanthemum. Most of the anemone’s color occurs because of the symbiotic relationship it has with the photosynthetic organisms that live in its tissues. Like other anemones, these attach themselves to hard surfaces—like rocks and coral reefs—to wait for fish that inadvertently swim into their stinging tentacles.

Purple Coral

The vibrant hue of this lilac-looking purple coral isn't the only striking thing about it: Though the color is rare, acropora coral is one of the most plentiful types of coral. It's immensely beneficial, too, as it provides a habitat for fish and other sea life.

These corals are also a reef-building species, which means they're often the first on the scene of a new reef, and they spread to provide homes for other corals.

Clownfish

Only one kind of fish is immune to the stings of the anemone, and, as anyone who has seen "Finding Nemo" knows, it’s the beautifully colored clownfish. Not all clownfish or all sea anemone are able to coexist, but for those that can, the relationship is mutually beneficial. The symbiotic process between the two is highly evolved, and involves the clownfish developing a thick mucus layer to protect it from the anemone’s powerful sting.

Sun Coral

Despite the name, sun coral are a species of coral that don't require much sunlight. They are deep-sea dwellers that make their homes in caves and other dark spaces. They get the energy they need (and their yellow to bright-orange color) by feeding on zooplankton. They're also the only stony coral that set up permanent digs in the Caribbean after invading the ocean in the ballasts of ships coming from the Indo-Pacific, this coral's native ocean.

Kelp

Kelp is especially stunning when seen from below because it can look just like lush, leafy woodland. Nutrient-rich kelp may show up on the beach as torn piles of seaweed, but underwater it has a whole different life. A type of brown algae, this plant can grow up to 18 inches per day and can reach depths of up to 131 feet—hence why their habitats are called kelp forests.

When scientists stumbled upon a kelp forest in the Pacific Ocean in 2007, the discovery highlighted how much we still have to learn about the world's waters. Prior to this discovery, biologists thought kelp could not grow in warm tropical waters.

Soft Coral

Feathery soft corals make up this bouquet of brightly-colored sea life. Soft coral are members of the Octocorallia subclass, named for their "eightfold radial symmetry," which means they have eight smaller pieces that branch off of each main tube to give the downy appearance.

Soft coral, which have significant variation in shape and size, can thrive in deep water or shallow tropical water.

Open Brain Coral

It's clear how open brain coral got its name: The invertebrate—known scientifically as Trachyphyllia—exhibits a flabello-meandroid growth pattern in which curling valleys and fleshy walls are visible on its exterior.

A type of stony coral, open brain coral are near threatened due to the reduction of coral reef habitat and harvesting for aquariums. This species of coral is small, less than eight inches, and is both solitary and colonial. It may be found among other types of free-living coral. It is found in the warm, shallow waters of the Indo-Pacific.

Coral Reef

Not only will you find remarkable creatures in coral reefs; you'll also find that the reefs themselves are quite stunning. Coral varies in shape, size, and texture, but they are perhaps most admired for their variegation. The different colors they display are a result of photosynthetic pigments, fluorescent proteins, and nonfluorescent chromoproteins.

Of course, their brilliant colors are severely threatened by warming water temperatures. Rising temperatures result in a reduction in the amount of microscopic algae that produce the food corals need to survive, which can destroy coral or cause severe damage to their ecosystem. As of 2021, coral bleaching impacted some 75% of reefs globally.

Even the largest coral reef system in the world, the Great Barrier Reef, is dying. Other threats to coral reefs include pollution and overfishing.