Fish Care

Different types of coral and how to identify them

Yes, corals, which look like rock or plant, are actually animals. There are different types of coral which come in a completely amazing mix of colors, shapes and sizes. In fact, coral reefs are formed by symbiosis between corals and algae (zooxanthellae) that live within their tissues and provide animals with the products of photosynthesis (food), and its beautiful colors.

Coral colors range from green, brown, pink, yellow, red, purple or blue; the exact color will depend on the precise mixing of zooxanthellae algae present within its tissues, some corals are even known as fluorescent; these amazing color patterns are due to the incredible concentration of algae in the coral mountains, there are millions of the same algae as per square centimeter of coral.

They are invertebrate coral reefs within the Anthozoa class of the phylum Cnidaria. They usually live-in joint colonies of many similar polyps. Coral species include key rock builders living in the tropical oceans and secrete calcium carbonate to form a hard skeleton.

While there are many types of coral, when it comes to identifying them, the categories are generally different. There is also deep water and soft corals. Each of these coral species is unique in its structure and environment. There are more than two thousand different species of corals that make up colonies that play a major role in marine areas.

Hard coral

Hard corals are made up of strong calcium (limestone) and appear more like rocks. Each polyp secretes a exoskeleton made of calcium carbonate and an internal skeletal structure that stays in place even after death. As each generation of polyps dies and their exoskeletons remain, the corals grows larger and because each polyp is very small, the strong corals grow at a very small rate. Strong corals are scientifically known as “scleractinians”.

Types of Hard Coral
  1. Staghorn Coral

types of coral

Staghorn coral (Acropora cervicornis) is one of the most important species of natural coral reefs. Not only are these hard coral reefs one of the fastest growing species, and they provide a secure home for many marine mammals.

Staghorn corals are identified by their sharp, carved branches that form dense coral gardens often found in shallow water. Unfortunately, this poses a significant threat to Staghorn coral reefs.

  1. Pillar corals (Dendrogyra cylindricus)

types of coral

“Pillar Coral” by FWC Research is licensed under CC BY-NC-ND 2.0

This type of coral grows from the sea, but without a second branch. They can grow up to 2.5 meters (8 ft) in height. They can grow on both flat and loose sea levels to a depth of between 1 and 20 m (65 ft). It is one of the few species of hard corals whose polyps seem to be common during the day.

  1. Table Coral (Acropora)

types of coral

“File:Acropora latistella (Table coral).jpg” by Nhobgood Nick Hobgood is licensed under CC BY-SA 3.0

Table Coral is the same type of coral branch as Staghorn coral, but grows like flat plates. characterized by a rising stem and many intertwined branches spread horizontally to form a table-like structure. The coral shape of the table is ready to reveal their size as much as possible in the sun. The typical color of the coral table is brown or green, but it is illuminated by the many coral reefs that live under their plates.

  1. Brain coral (family- Faviidae)

types of coral

“Brain coral” by bob.bachand is licensed under CC BY-NC-ND 2.0

Named because of this condition of the coral spheroid and the grooved surface resembling the brain of an animal. Colonies can grow up to 1.8 meters or more.

  1. Blue corals (Heliopora coerulea)

types of coral

“Blue coral is outstanding at Gota Abu Ghusur Reef, Red Sea, Egypt #SCUBA #UNDERWATER #PICTURES” by Derek Keats is licensed under CC BY 2.0

Blue corals are named after their distinctive, permanent blue skeleton, usually covered with green or blue polyps. These types of coral are found in hot water, in flat-bottomed flats, and on high-slope corals.

  1. Great star coral (Montastraea cavernosa)

types of coral

“Great Star Coral (Montastrea cavernosa)” by nashworld is licensed under CC BY-NC-SA 2.0

This type of coral is a colony of colonial rocks found in the Caribbean. It forms large boulders and sometimes plates. They are Polyps the size of a human thumb and can be seen fully expanded at night.

         7. Elkhorn coral (Acropora palmata)

types of coral

“Acropora palmata (elkhorn coral) (San Salvador Island, Bahamas) 1” by James St. John is licensed under CC BY 2.0

As the name suggests, these types of coral look like horns of deer or elk. This coral is considered one of the most important coral reefs in the Caribbean. This type of coral is complex with the formation of many large branches. Popular options such as home lobster, parrot-fish, snappers and other marine fish. Elkhorn coral colonies grow very fast with an average growth rate of 5 to 10 inches (2.0 to 3.9 in) per year and can eventually grow to 3.7 meters (12 ft) in diameter.

 Soft Coral

Soft corals are generally similar to plants and trees. They are soft and flexible and therefore do not have stone structures such as hard corals. For protection and support, they grow wood-like characters for stability. These cores are made up of proteins of structures such as gorgonin and other proteins such as those of the nails and horns of other animals. These types of coral are called Ahermatypes. Examples of soft corals are in the Bahamas and the Caribbean include sea fingers or sea whips. This type of coral also does not always have a relationship with zooxanthellae. This gives the soft coral some protection and support. The species is soft and prefers to live in rich, nutritious water with very little light.

Types of soft coral
  1. Coral Trees (family-Nephtheidae)

“Tree coral with Wrasse in Fiji” by Derek Keats is licensed under CC BY 2.0

These delicate flowering corals are abundant on many shores. They are usually attached to solid surfaces including rocks, jetty pilings and coral rubble. These soft corals look like trees. The thick ‘big stem’ sticks to the solid surface on one side, there are many small branches on the other side which is why it is called Tree Coral.

      2. Organ Pipe Coral

“笙珊瑚 pipe organ coral” by wlchui is licensed under CC BY-NC-SA 2.0

Each Organ Pipe Coral tube has 8 individual tentacles.

Organ Pipe coral, or Tubipora Musica, is perhaps the most appreciated human species.

Although this type of coral is considered to be soft coral, it has strong bones that hold each soft tube. All of these tubes have a feathered head of tentacles, which are used to feed on plankton.

Organ Pipe corals are found in shallow water, and prefer protected areas.

  1. Sea Whip Coral

“Whip coral at wheeler reef” by Cruising, traveling & dive pics. is licensed under CC BY-NC-ND 2.0

The Sea Whip is part of the magnificent gorgonia coral family.

Branches like the Sea Whip coral come in eye-catching colors including red, orange, yellow, and purple.

These coral reefs are commonly found in deep water, living on walls and rocks, growing up to three feet.

  1. Venus Sea Fan Coral

“Sea Fan” by Peter Nijenhuis is licensed under CC BY-NC-ND 2.0

Venus Sea Fan is a fragile species of coral. Found mainly in the Bahamas and in the West Indies, this beautiful soft coral is composed of an intricate chain of branchlets that grow on a small base.

Venus Sea Fan coral comes in white, yellow and lavender colors. Their favorite place is the shallow water is with strong waves at depths of up to 30 feet.

  1. Bubble Coral

“Bubble Coral on the Unkai Maru” by mattk1979 is licensed under CC BY-SA 2.0

The bubble coral, or Plerogyra sinuosa is one of the most interesting species of coral species. Usually found in at a depth of 3-35 meters, Bubble coral is often mistaken for fish eggs.

During the day, these white / skinned polyps look like blisters or clusters of grapes, but at night the small balloons loosen, allowing their cords to come out and hunt for food.

Bubble corals can be found in coral reefs such as the Red Sea and the Indian Ocean in the middle of the Pacific.

  1. Carnation Coral (Dendronephthya)

“Carnation coral (Pectinia sp.) bleaching” by wildsingapore is licensed under CC BY-NC-ND 2.0

The carnation coral comes in a variety of vibrant colors and thrives beneath the underhangs and caves. They are found mainly in the Indo-Pacific – Islands of the Indopacific including Fiji, Tonga, Solomon Islands and the Great Barrier Reef.

Carnation coral thrives in high-energy areas, and it usually grows on walls or under rocks. When the current is active, these corals multiply and bloom to feed, but in the absence of current, they sink to the bottom.

  1. Toadstool Coral (Sarcophyton)

“Toadstool coral (Sarcophyton sp.)” by krokodiver is licensed under CC BY 2.0

Also known by other names such as Leather Coral, Mushroom Leather Coral and Trough Coral Sacrophyton coral is available in various shades of brown, with white or gold particles. It is difficult to identify many species because they all have the same mushroom or toadstool appearance, each with a different stem and capitulum (cap). As they grow, they have a curved appearance.

  1. Gorgonia

"Gorgonia coral on Golden Blocks reef, Dahab" by mattk1979 is licensed under CC BY-SA 2.0

“Gorgonia coral on Golden Blocks reef, Dahab” by mattk1979 is licensed under CC BY-SA 2.0

This family of soft corals is also called sea fans or sea whips. Some may be like a whip. The colony can be several meters high and thick but a few inches in diameter. They are usually purple, red, or yellow. Gorgons are found mainly in shallow water, or some are found in depths of several thousand feet. Fan shaped gorgons prefer to live in shallow areas with strong currents, while the taller, thinner, and stronger gorgonians prefer to live in deep, calm waters.

Deep Sea Corals

“Deep-Sea Coral” by Green Fire Productions is licensed under CC BY 2.0

Deep sea corals can be found at depths of up to 6,000 m (20,000 ft) below sea level. These types of  coral live in cold, shallow waters with little sun. These corals, as shallow species, can exist as single or multiple polyps, living in complex colonies composed of different species. Since these species do not need sunlight or warm water, they are able to grow in many waters around the world. They have even been found in cold water as -1-degree celsius. As these corals live outside the sun, they contain zooxanthellae. This means that these corals must find their energy and nutrients elsewhere.

The main reason many scientists did not know that there are these deep coral reefs is because, for many years, the depths of the sea were inaccessible. In addition to the astounding diversity, scientists have also discovered that deep coral reefs are among the oldest recorded marine life.


Corals can be gonochoristic and hermaphroditic, each of which can be reproduced sexually and asexually. Breeding also allows corals to adapt to new habitats. Reproduction involves chemical interactions. Corals are very sexually reproductive.


Polyps feed on a wide variety of micro-organisms, from small zooplankton to small fish. Polyp’s tentacles catch or kill using stinging cells called nematocysts. These poison-carrying cells are rapidly release in response to contact with another organism. The flap (operculum) opens and its stinging tentacles burn the barb fish into the prey. The venom is injected with a loose filament to immobilize the prey, the tentacles then maneuver the prey into the stomach. Once the victim has been digested the stomach opens and allows for the elimination of waste and the start of the next hunting cycle.

Do corals have predators?

Several actually, there are other predators that are part of the normal life cycle of corals such as parrotfish and turtles, who will eat coral reefs as part of their daily routine. On the other hand, there is only one carnivorous animal that can devastate a reef and that is the crown of thorn starfish. When an outbreak of this starfish occurs in the reefs, the destruction is out of control and reaches the epicenter and completely destroys the reef within a few months.

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