Coral reefs are made up from coral (which itself is an animal), that exists with other animals such as sponges and sea slugs. There are two main types of coral reef habitat which are hard coral reefs and soft coral reefs. Soft corals are individual animals (known as polyps) which move through the waters, and eventually settle. The hard corals are the reef-building corals and often consist of dead corals which have left a hard coral shell behind them when they die.
Coral reefs are habitats that are so rich in life and biodiversity, that many different animal species are able to live together as there is no competition for food. Coral reefs are found in the world's tropical and sub-tropical coastal regions where it is always warm and never cool, even at night. The largest coral reefs can be found in the Caribbean, the south-west coast of Africa, and all around south-east Asia, Australasia and throughout the coastal regions of the South Pacific Ocean.
Numerous different animal species inhabit coral reefs around the world and vary tremendously in size, shape and colour. Starfish, sea urchins and crustaceans are the most commonly found invertebrates on coral reefs, and countless species of fish including seahorses and eels can also be spotted with ease. Many species of sea snakes live in coastal waters particularly around south-east Asia, hunting small fish and eels in the coral reefs.
Other animals may not inhabit the coral reefs permanently, but will pay frequent visits to the them in order to find food. Sharks are the most commonly found predators around coral reefs as they either feed there while they are passing or visit on a regular basis. Sea turtles can also be seen around coral reefs as they hunt for food, but they do not permanently exist there are they spend their lives swimming in the open ocean alone.
The biggest threats to coral reefs and coastline wildlife are pollution, storms and commercial fishing. Dredging, is a type of fishing method that involves dragging the nets across the sea bed in order to get more fish. This method of fishing is extremely destructive to coral reefs particularly when so many of them are filled with animal species that are already on the brink of extinction (including many species of coral). Sea storms such as tsunamis can also have a devastating effect on coral reef communities, as one large wave can tear apart a whole reef community in an instant.