Coral Reefs

Coral Reefs

Underwater Communities Coral reefs are huge ocean communities. Millions of animals and sea plants live in them. Coral reefs are very busy places. Many kinds of coral make up reefs. Corals aren't rocks or plants. They are tiny animals called polyps(PAH-lips). Most polyps are smaller than a pea.

Kinds of Coral There are two kinds of coral. The first kind is hard corals. These corals have hard skeletons. Over time, thousands of polyp skeletons help build a reef. Algae (AL-jee) live in the bodies of these corals. Algae are simple cousins of plants. The algae are food for the corals.

Soft corals are the second kind of coral. They often look like trees or other plants. These corals can bend with the water currents. Algae live in the bodies of some of them. Many corals are named for what they look like. Brain corals look like brains. Sea fans look like open fans. Sea pens look like old-fashioned pens made from big feathers.

A Busy Home Thousands of fish of all sizes, shapes, and colors live on reefs. They depend on the reef for food and safety. Shrimp, lobsters, crabs, and sea stars feed on reefs. The holes in reefs are good places for animals to hide

Where Corals Live Most coral reefs are close to shore in warm parts of the world. Corals need certain things to stay healthy. They need algae for food. They must be near the water's surface so the algae can get enough sunlight. Also, both corals and algae need water that is not too warm or cold. There are three kinds of coral reefs Fringing reefs are close to the shore.