Coral reefs make up less than 1% of the ocean floor but are home to about one-quarter of all marine biodiversity. Providing sustenance to hundreds of millions of people worldwide, coral reefs also act as natural shock absorbers, protecting low-lying communities from wave surge. These magnificent ecosystems are however in grave danger due to human-caused climate change that is warming and acidifying the world’s oceans. Our film introduces the coral holobiont and explains how scientists are using modern genomics tools to aid coral reef conservation.