National Aquarium - Coral Reef

Coral Reefs

Watch Pacific Coral Reef  live:

Bright, beautiful and overflowing with life, coral reefs are among the most incredible natural wonders in the world.

Often thought of as rocks or plants, corals are actually made up of invertebrates called polyps. These polyps can range in size from a millimeter to a foot in diameter. The polyps group together, forming a colony, and use calcium carbonate from the ocean to build a protective skeleton.

Generally, corals are classified as either hard or soft corals. Hard corals are the framework of the reef. As these corals grow in colonies, they create skeletons. Soft corals are soft and bendable, looking more like plants. These organisms form a visually stunning and biologically important foundation for many ocean inhabitants, from tiny fish to large apex predators like sharks.

The Value of Coral Reefs

Though coral reefs constitute less than one percent of the ocean floor, they support an estimated 25 percent of ocean life, serving as critical spawning, nursery, breeding and feeding grounds for thousands of species.
- Jack Cover, General Curator, National Aquarium

The loss of thriving coral reefs has real consequences, and not just to their many inhabitants. Besides being essential habitats for fish, coral reefs have a measurable value to those who live on land. Because they essentially serve as mountain ranges for the ocean's coastlines, they deflect the energy of brutal storms that might otherwise decimate coastal communities. In fact, in areas where we have experienced tsunamis, the areas with coral reefs fared much better than those without.

Chemical compounds unique to coral reefs are especially useful for medicinal purposes. Researchers have used coral amalgams to treat ailments including ulcers, skin cancers and heart disorders. Once the correct formula is identified, the medicines can be synthetically mass-produced .

And of course, the natural beauty of coral reefs makes them attractive for tourists, too. Visitors from all over the world flock to the Florida Keys, Barbados, Indonesia, Australia and other destinations to get a closer look. Most of these areas rely heavily on tourism for economic growth and sustainability, so preserving coral reefs is vital to their economies.

All told, the economic value of coral reefs has been estimated to be $375 billion per year.

Reef in Danger

Sadly, coral reefs are highly threatened. Storm damage, invasive species, climate change, coastal development and commercial use are just a few of the threats. Corals are extremely sensitive, so even small sifts in light, temperature and water acidity can be detrimental. Many of the choices that we make every day contribute to the devastation of coral reefs. Coral is able to grow and repair itself, but needs precisely the right environment to do so.

In order for many coral species to thrive, they must have exposure to bright sunlight. Clear-water environments are necessary for corals to receive the maximum amount of direct light. Pollution in our water from runoff and other chemicals can cause excessive amounts of algae to grow on its surface. This process, called eutrophication, clouds the water and prevents coral from getting the sun that it needs.

According to a report by the World Research Institute, 75 percent of the world's reefs are considered threatened.

In addition to chemical pollutants, coral reefs are also threatened by ocean acidification caused by the burning of fossil fuels. This process sends a deluge of carbon dioxide into the air, forming carbonic acid. Destructive fish practices, such as the use of cyanide to attract specific types of fish, also contribute to the devastation of coral reefs.

While the future of coral reefs may appear bleak, there's still a lot we can do to protect these aquatic treasures! The individual choices that we make each day CAN make a difference in the future health of our ocean.


Meet Our Coral Reef Inhabitants

  • Anemones

    Sea anemones are polyps that attach to surfaces with an adhesive foot, called a basal disc. Their column-shaped bodies end in an oral disc, and they can have anywhere from a dozen to a few hundred tentacles.

  • Banggai Cardinalfish

    This small, disc-shaped fish is easily recognized by its tasseled first dorsal fin; long, tapering second dorsal fin; and deeply forked tail, or caudal fin.

    Banggai cardinalfish
  • Bonnethead Shark

    While many of our visitors point and declare “hammerhead!” when they see this shark cruising through the exhibit, the bonnethead shark is easily distinguished from its much larger cousin.

    Bonnethead shark
  • Green Moray Eel

    The green moray is actually brown! The yellow tint of the mucus that covers its body, in combination with the drab background color, gives the fish its namesake green appearance.

    Green Moray Eel
  • Percula Clownfish

    The percula clownfish is the most well known of the 29 species of clownfish.

  • Sea Stars

    There are nearly 2,000 species of sea stars in the world’s oceans.

    National Aquarium – Sea Stars
  • Spotfin Porcupinefish

    Like most pufferfish, the spotfin porcupinefish can draw in water to inflate itself. When it does, sharp spines on its body stick out, which is how it got its name.

    National Aquarium – Porcupine Fish
  • Yellow Sea Cucumber

    As a defense, yellow sea cucumbers can expel their internal organs—then quickly regenerate them.

    National Aquarium - Yellow Sea Cucumber
  • Yellow Tang

    This reef-dwelling fish is known for its bright yellow body.

    National Aquarium - Yellow Tang

Back to the Top