Live Vs Dead Coral – See the Difference

This page will help you tell the difference between what live vs dead coral looks like. With rising ocean temperatures, damage from tourism, and overfishing, it’s estimated that 25%-50% of the world’s corals reefs are already dead, up to 75% have suffered bleaching events, with the remainder at risk. Finding a live healthy coral reef is actually becoming rare.

Many people have their first snorkeling experience at popular tourist locations like Hanauma Bay, Oahu in Hawaii, or Trunk Bay in St. John.  Since most of the coral at these locations is dead many new snorkelers may not realize what they are missing, or what live vs dead coral looks like.

Coral Looks Like a Stone or Plant, But It Is a Colony of Animals

Coral is like the forest of the sea, except it is not a plant, it is a colony of animals (called polyps).

For comparison of live vs dead coral, this is a live coral polyp colony with their polyps retracted.

These little animals live in a symbiotic relationship with algae, and they build tiny calcium stone houses for themselves. And all of these houses get stacked on top of each other and form larger structures like apartment buildings or termite hills. These can take many different shapes that might look like hard rock boulders, or branches. They can also form flexible structures that can move with the currents of water. In the closeup picture you can see the structure of their calcium houses. The animals are withdrawn inside. Many corals only come out at night to feed, although there are some exceptions.

For example the first picture below is a leather coral (partially bleached), and the animals are mostly retracted. The next picture shows the animals out feeding.

Partially bleached leather coral with retracted polyps
Leather coral with polyps out feeding

Here is an excellent article that explains coral animals.

It’s sometimes hard to think of corals as animals, but they are. They often feed on zooplankton that they pull inside and digest in stomachs. Aquarium owners often feed their corals with brine shrimp.

What Live Vs Dead Coral Looks Like

Check out the pictures below. These are just a few samples of some common corals that can be seen in the Pacific and Atlantic Oceans.

Compare what live vs dead coral looks like. Look at the color and shape. Old dead corals will be broken down, and lack a healthy color, and are sometimes covered in algae.

Corals that have been bleached from rising ocean temperatures turn white when the symbiotic algae leaves the coral. In some rare circumstances these may recover if the algae returns.

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Dead or Dying Elkhorn Coral

Snorkeler swimming over a dead Elkhorn Coral
Mostly dead Elkhorn Coral
Partially dead Elkhorn Coral with Brown Chromis

Live Elkhorn Coral

Healthy stand of Elkhorn Corals

Foggy Masks, Fin Blisters and Angry Snorkels!

Poorly fitting, cheap gear, can ruin your trip. See our snorkeling equipment reviews and fitting suggestions to make sure your next trip is great.

Dead, Unhealthy, or Damaged Brain Coral

Unhealthy Symmetrical Brain Coral
Grooved Brain Coral where parts have been damaged and are now dead
Diseased and dying Symmetrical Brain Coral

Live Brain Coral

Healthy Symmetrical Brain Coral
Healthy Boulder Brain Coral

Unhealthy Sea Fan Corals

Only the center purple fan looks relatively healthy in the picture below. Soft corals like these also have tiny polyps that feed on microorganisms in the water.

Sea fans in mixed health

Live Sea Fan Coral

Healthy Sea Fan

Dead Staghorn Coral

Field of mostly dead Staghorn Coral

Live Staghorn Coral

Live Staghorn Coral

Bleached Table Coral, Soon to Be Dead

Bleached Table Coral

Mix of Live and Bleaching Table Corals

Mix of live and bleaching Table Corals

Bleaching Boulder Coral

Big Boulder Coral in the process of bleaching

Live Boulder Coral

Live Boulder Coral

Live vs Dead Coral – Cauliflower Side by Side

Live vs dead Cauliflower Coral, side by side
Live Cauliflower Corals next to a dead one

Algae Sometimes Takes Over a Dead Reef

When you are trying to see if something is live vs dead coral, one way to tell is that dead coral often becomes covered in algae like in the picture below.

Algae covering a dead coral reef

Corals Are Critical for Healthy Oceans

Corals clean the oceans, provide habitat, and are food to countless other species. And we are seeing a global mass extinction on a scale that is terrifying for not only ocean health, but human fisheries. Without coral reefs, human jobs and food sources are rapidly declining.

So the next time you are out snorkeling, and see some beautiful fish, like in the pictures below, make sure and look behind at the coral, and take note of its condition. The corals are 95% dead in the two pictures below. Without corals, you can expect the ocean’s entire ecosystem to be stressed and declining.

Lots of fish over dead coral reef
Dead coral reef

What Can You Do?

Helping prevent the continued destruction of coral reefs is pretty easy, on a personal level at least.

  1. Learn to recognize the live vs dead coral on the reef.
  2. Only use sunscreens that don’t kill reefs, or wear a full body rash guard.
  3. Don’t touch or kick coral, use good reef etiquette.
  4. Fight the human causes of global warming any way you feel you can. Support an ocean charity and vote for good policies.

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