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What is coral?

Quick answer from Eartha

Coral is actually a tiny living animal, not a plant or a rock! Thousands of little coral animals called polyps live together and build hard, colourful skeletons around themselves. Over time, these skeletons join up to form huge coral reefs, which are like busy underwater cities for fish and other sea creatures.

The longer story

Coral might look like colourful rock or plants, but it's actually made of tiny living animals called polyps. Each polyp is soft-bodied and about the size of a pinhead, with little arms for catching food.

Polyps build hard skeletons around their soft bodies using minerals from the seawater. When thousands of polyps live and grow together, their skeletons join up to form the shapes we recognise as coral.

Many corals also have a special partnership with tiny algae living inside them. The algae make food using sunlight and share it with the coral, while also giving coral its bright colours.

Coral reefs grow incredibly slowly, often just a few centimetres each year, which means big reefs can take thousands of years to form. That's why looking after coral today matters so much for the future.

Try this at home: Build a coral colony

  1. Use playdough or building blocks to make lots of small, similar shapes.
  2. Join them all together into one big cluster.
  3. Talk about how thousands of tiny coral animals build a reef the same way.

Words to know

Polyp
A tiny soft-bodied animal that builds a hard coral skeleton.
Algae
Simple plant-like living things that can make their own food from sunlight.
Reef
A large structure built from many corals growing together.

For grown-ups: what is my child learning here?

Age band: 5-8

Curriculum link: Australian Curriculum v9 Science, AC9S3U01 - living things and their environments

The concept: Teaches that coral is an animal, addressing a common misconception.

More classroom ideas are on our teachers page, and safety notes for families are on for parents.

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