A cutaway view of a coral reef, from the sandy floor up to the surface, filled with fish, sea turtles, a crab and branching coral.🪸 There is a great deal to fill in, which suits older children who like a detailed page — and it doubles as a science lesson. Give every fish its own colors and the whole reef comes alive.
PDF (line art) and PNG (line art and color sample)
How does a coral reef form?
Coral is an animal, not a rock or a plant. Each tiny polyp builds a hard skeleton of calcium carbonate around itself, and when it dies the skeleton stays behind for the next generation to grow on top of. Repeat that for hundreds or thousands of years and the result is a reef.
What lives on a coral reef?
Reefs cover only a sliver of the sea floor, yet they are often said to shelter around a quarter of all marine species. Clownfish, sea turtles, grouper, octopus and shrimp all appear somewhere in this picture. Reefs are sometimes called the forests of the sea, for much the same reason.
Why does coral turn white?
It is called bleaching, and it happens when the water stays too warm. Corals host microscopic algae called zooxanthellae that supply both their color and much of their food; when the sea heats up the algae leave and the bare white skeleton shows through. A bleached coral is not dead yet, but it will not last long unless conditions cool again. Warming seas are the main driver.
