Still images showing corals of many sizes, shapes and colors growing on a reef.
Voice: Corals are relatives of jellyfish and can sting you. Some are soft, while others form hard skeletons that grow into underwater hills that we call reefs. Millions of animals and plants depend upon these reefs, including people. Tiny plants live inside the soft part of the coral using it for protection and giving the coral extra food. These plants are what give corals their colors. Corals are very sensitive to temperature changes and pollution. When they are stressed they will spit out these tiny plants. This makes the coral look white, like they were dipped into bleach.