If you believe that coral reef is some kind of a thing, you're missing out quite a vital fact—it consists of small organisms, and therefore it represents a living community, precisely —a colony.
Once a year after a full moon in October or November all coral reefs around the world spawn. This fact concerns many scientists who have not yet found a definite answer to the nature of the phenomenon. There are several theories, indicating the triggers of the spawning with the rise of sea temperatures, lunar cycle and diurnal cycle among others. These reasons turn the coral reefs into a romantic mood and they start to release sperm and fertilise the eggs. The sea then turns into champaign-bubbly kind of water and the colourful reefs shine spectacularly.
However, you will need to be careful with the dates if you want to see the miracle since you will have to check when is the full moon.