Difference Between Coral and Reef

Coral vs Reef

Coral and reef often come together in the form of coral reef, yet the two are different entities that function as a unit. Both corals and reefs bring a lot of interests for biology in general and for ecology and environmental science in particular. When both coral and reef are further studied, additional differences between them could be understood.


Coral is a cnidarian in the Class: Anthozoa living in the marine environment. Corals live in colonies that are composed of identical individuals in the polyp form. Being invertebrates, coral polyps do not have an internal skeleton, but they secrete calcium carbonate that forms a hard skeleton around each coral polyp. This exoskeleton is usually formed around the base of the polyp, and the secretion is continued over many generations, which create a large reef eventually. The shape of the exoskeleton is characteristic for each species.

Difference Between Coral

There are more than 70,000 different species of corals in the world, and the vast majority of them inhabit the tropical warm marine waters. The common name referred for each coral species has been usually based on the external appearance of the exoskeleton, which is resulted from the secretions of the polyp colony. It would be important to state that there are two main types of corals known as Hermatypic (reef-builders) and Ahermatypic. With the presence of various colours in the live polyps, coral colonies present an attractive and colourful appearance to their environment. One of the features that attract the coral watchers is this beauty of the corals.

Corals feed on other organisms such as plankton and small fish, by immobilizing the prey via nematocysts. Asexual reproduction is most common in corals, but sexual reproduction via spawning is also present among them. Spawning is very interesting as it occurs synchronously with the other species during the same night. Although they are made of animal cells, as they are so classified, corals appear as ever blooming underwater gardens.


Reef is a physical structure that has been formed underwater through either biotic or abiotic processes. The best-known reefs are the coral reefs, which have been resulted through the biotic process known as reef formation by live reef-building corals in tropical marine waters. In addition to these natural reefs, there may be artificial reefs such as shipwrecks on the seafloor. It is highly interesting that such artificial reefs provide highly complex habitats for fish and other marine organisms so that they can hide from predators easily.

Biotic reefs such as coral reefs and oyster beds are of great ecological importance, providing habitats for a range of organisms from microscopic algae up to massive vertebrates. Depending on the place and shape of the biotic reef, there are three main types known as Fringing reef, Barrier reef, and Atoll reef. Fringing reef is attached to the land, while barrier reef is formed slightly away from the land forming a lagoon that is protected from waves, whereas atolls are formed where there is no land around.

Difference Between Coral Reef

It would be important to notice that the ever loving coral reefs are formed through the secretion of calcareous exoskeleton by the coral polyps. Reefs are extremely important physical structures that provide habitats for a vast range of organisms.

What is the difference between Coral and Reef?

• Coral is a live animal while reef is a physical structure.

• Reef is the habitat of the corals, which has been created through the secretions of coral polyps over many generations.

• Corals are always live while a reef could be resulted through either biotic or abiotic processes.