Coral Lesson for Kids: Definition & Facts

Instructor: Diane Sieverson

Diane has taught all subjects at the elementary level, was the principal of a K-8 private school and has a master's degree in Measurement and Evaluation.

There are many different kinds of coral that live in the ocean. Come learn about coral, whether it's a plant or an animal, how it gets its food, why it's important, and some other cool facts about it.

What is Coral?

Imagine swimming in the ocean where the water is shallow. When you look through your mask, you see a rainbow of color, but you aren't looking at the fish. The structures you see are attached to the sea floor and some even sway in the water. You are looking at coral!

Even though it looks like a plant, coral is an animal that lives in tropical water, stays in one place, and lives in groups. Some kinds build a hard skeleton on rocks to hold themselves up.

Coral polyps
Coral polyps

These animals, called coral polyps (pronounced POL-ips), attach themselves to a rock by building a solid skeleton-like base to hold it in place, the way roots hold a tree in the ground.

Once the coral polyp is attached, it creates new polyps that group together to make colonies. These living colonies connect to other coral colonies and form big groups called coral reefs. Some reefs are more than 50 million years old!

Just like you have relatives, coral is related to jellyfish. It can even sting!

Hard and Soft Coral

Within a coral reef, you may see both hard and soft coral. The two kinds are easy to tell apart.

  • Hard coral forms the structure of a reef. After this kind of coral attaches itself to the rocks, it builds a hard, sharp skeleton that doesn't move, like the frame of a building. There are many different kinds of hard coral, including brain coral. Brain coral got its name because it looks like a brain!

Brain coral
Brain coral

  • Soft coral doesn't build that hard skeleton, so it attaches and supports itself using sharp spikes. It doesn't create reefs, though soft coral sometimes lives in hard coral reefs. This kind of coral sways as the water moves and it's usually more colorful than hard coral. It also doesn't want to be a snack for a hungry fish, so it makes chemicals that taste bad and can even be poisonous. Sea fans are one kind of soft coral.

How Does Coral get its Color?

Some coral has a chemical in it that makes it colorful. But other coral gets its color from algae, which is a plant that grows on it.

Colorful coral
Colorful coral

However, that algae isn't there for decoration. It makes food for itself and the coral, too. Coral gets a lot of its nutrition from the algae's food, but it's also carnivorous, which means it's a meat-eater.

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