Along with the need to have clear, unpolluted water, coral reefs need sunlight to thrive. Sunlight is how corals get their oxygen, and many of the diverse ecosystems that live within its depths also require steady sunlight to live.

Does coral reefs get sunlight?

Sunlight: Corals need to grow in shallow water where sunlight can reach them. Corals depend on the zooxanthellae (algae) that grow inside of them for oxygen and other things, and since these algae needs sunlight to survive, corals also need sunlight to survive.

How much light does a coral reef get?

Over the years hobbyists have discussed crude measurements of the amount of light corals need to thrive. Most successful reef aquarists will use about 6-8 watts of light per gallon of tank water, more in deeper tanks and less in shallower tanks.