These kaleidoscopes of colour and life cover less than 0.1% of the planet but are home to a quarter of all marine species.
As a result, it’s a crowded place to live and underwater warfare reigns as animals vie for space and food.
Since many of the creatures on the reef are stationary, many have evolved chemical defences to protect themselves from predators.
These potent weapons may also hold the key to new medicines to treat everything from cancer and Alzheimer’s disease to viruses and arthritis.
Scientists have already collected and identified thousands of these compounds and are bringing treatments to market.
But coral reefs face an uncertain future putting this undersea medicine cabinet at risk.
In this film ecological economist Dr Trista Patterson, lead scientist with The Nature Conservancy Dr M Sanjayan and marine conservation biologist Professor Callum Roberts reveal the richness of life supported by coral reefs and the contribution these colourful ecosystems are making to medical science.