Corals are animals · Coral UnderseaScience for kids

Is coral an animal or a plant?

In short: Coral is an animal. Each coral is made of many tiny animals called polyps, which are relatives of jellyfish and sea anemones. Many reef-building corals also have microscopic algae living inside them, and the two help each other.

Corals are animals: a nature card illustration

How it works

A coral polyp has a soft, bag-like body with a ring of tentacles around its mouth. The tentacles carry stinging cells that catch tiny drifting creatures to eat. Reef-building hard corals also make a stony skeleton from substances in seawater, and over many generations these skeletons build up into reefs.

Many reef-building corals have tiny algae called zooxanthellae living in their bodies. The algae use sunlight to make food by photosynthesis and share some of it with the coral. In return, the coral gives them shelter and the ingredients they need. The algae also give many corals their colour.

Because their algae need sunlight, reef-building corals mostly live in warm, clear, shallow tropical seas. Coral reefs cover only a tiny part of the ocean floor, yet they are home to a huge variety of fish and other sea life, which is why they are called rainforests of the sea.

Where to see it in New Zealand

New Zealand's waters are too cold for big coral reefs, but corals do live here. In the fiords of Fiordland, black coral grows. Alive, it looks white; only its skeleton is black. A dark layer of fresh water on the surface blocks sunlight, letting this usually deep-water coral grow unusually shallow.

Try it together

With an adult, visit a rock pool at low tide and look for sea anemones, close relatives of corals. Crouch down and watch how their tentacles sway in the water. Look but do not poke or move them, watch for slippery rocks and stay away from big waves.

Kids also ask

Is coral a rock?

No. The white coral pieces you sometimes find are skeletons left behind after the polyps died. Living coral is covered with a layer of soft polyp tissue that eats, grows and reproduces.

How does coral get its food?

In two main ways. Polyps catch drifting plankton with their tentacles, often at night. They also receive food from the algae living inside them, which is often their main source of energy.

In the game, “Corals are animals” is a nature card on Coral Undersea.

Your child finds this card by reaching the right place or meeting the right weather on the island, and lights it up by answering the question on the back. Tap the button below and the game shows your child which island it is on and how to find it. Mochi Isle is a browser learning game for ages 5 to 18; the main island and the daily lesson are free.

Find “Corals are animals” on the island ↗ All cards from Coral Undersea