A thriving ocean depends on a healthy reef because as corals grow, they build complex habitats with lots of nooks and crannies for juvenile fish. But diving on a Caribbean reef can be overwhelming, with so much to see. Knowing some basic Caribbean coral identification means you’ll enrich your experience, so you’ll see beyond the bustling reef fish on each dive.
A hard, calcium-carbonate skeleton is the definitive feature of hard corals. As the coral polyps grow, they create a structure called a corallite, which is the polyps’ home. Below are 11 common species of hard coral that you can find while scuba diving in the Caribbean, as well as some tips on how to identify them.
The Caribbean staghorn coral (Acropora cervicornis) is an important reef-building species because the long, pointed branches intersect as they grow upward towards the sun. This creates a three-dimensional lattice, perfect for juvenile habitat. The branches of this coral are particularly vulnerable to errant fin kicks, so be careful when swimming around these corals. Acropora cervicornis is the only staghorn coral in the Caribbean, but any Acropora species around the world that forms long, thick branches is considered a staghorn coral.
The Caribbean elkhorn coral (Acropora palmata) is a robust species that forms large colonies that can grow to be bigger than a human. As the branches grow, they fuse together to form broad branches, which break apart into flat blades near the edges of the colony. As this coral grows and completes its life cycle, dead elkhorn skeletons add rock and mass to the reef. Therefore, we consider them a reef-building coral. Caribbean elkhorn coral is endangered, with coral-restoration projects in the region focusing mainly on restoring elkhorn and staghorn acropora species.
This type of coral is common in the Caribbean and several species form plates and blades with intricate corallites. The scientific name for lettuce coral is (Agaricia). This coral can be gray, yellow, or brown, and some have bright green polyps. This coral grows anywhere from caves to the brightest shallow reefs.
Great Star Coral
As the name implies, this coral grows into large colonies. In the shallows, great star coral (Montastraea cavernosa) forms large domes or wide columns, but in deeper, darker water, this coral tends to spread out wide to catch more of the available light. Montastraea grows in a range of colors. Keep your eyes peeled for bright orange or pink colonies.
Mountainous Star Coral
The corallites of this coral (Orbicella faveolata) are much smaller than those of the great star coral. They have several uniform lines running from the top of the corallite, giving it a star like appearance. The mountainous star coral forms large sprawling colonies with peaked ridges running down the side of the colony, which is why we call it “mountainous.” Orbicella is common in the Caribbean and grows in mostly blue, gray, yellow, and brown.
Pillar coral (Dendrogyra cylindrus) is one of the Caribbean’s most unique corals. The polyps of this coral extend during the day giving it a fuzzy appearance. When the polyps are retracted, the skeleton has corallites that twist and turn throughout the colony, giving it a maze-like appearance. Pillar coral is rare on most Caribbean reefs. It’s listed as vulnerable because recruitment and survival rates of juveniles is low.
Mustard Hill Coral
This coral (Porites astreoides) is named for its vibrant yellow color. As the coral grows, it forms lumps and bumps all over the surface of the colony. Porites astreoides also grows in blue and gray colonies throughout the Caribbean. You’ll find this common coral on all parts of the reef, from the shallowest to the deepest.
Grooved Brain Coral
The scientific name for grooved brain coral is Diploria labyrinthiformis. This coral forms wide, brain-like ridges, with a noticeable groove in the center of each ridge. The colonies can build large domes or more encrusting forms along the sea floor. Search for the wide, grooved ridges to identify this coral. Colonies can be several feet across and you’ll find them in all habitats.
Smooth Flower Coral
During the day, you might wonder how this coral (Eusmilia fastigiata) got its name. But on a night dive, you’ll see a large, fleshy, flower-like polyp emerge from the skeleton to catch a passing meal. Eusmilia grows into trumpet-like corallites around one inch long. Corallites are connected at the base, and colonies can grow quite large with hundreds of polyps. More commonly, you’ll see small colonies with a dozen or more corallites. The color is always creamy white or yellow.
Solitary Disk Coral
Solitary disk corals, (Scolymia sp.) are the diamond in the rough. Scolymia are the most colorful coral in the Caribbean, appearing in bright red, pinks, greens, gray, purple and brown. There is no telling what color a Scolymia will be, which is what makes searching for this coral so much fun. There are two species of Scolymia; S. cubensis and S. wellsi
Rough Cactus Coral
This coral forms large plates that spread along the sea floor or on the sides of rocky reefs, but the first things that will catch your eye with rough cactus coral (Mycetophyllia ferox) are the bright pink corallites. Although Mycetophyllia have a soft, fleshy appearance they are hard corals, sporting a hard skeleton underneath.