What is the difference between stressed and bleached coral?

When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white. Warmer water temperatures can result in coral bleaching. ... This is called coral bleaching. When a coral bleaches, it is not dead

Explanation:

and after water is usually warmed by the sun the water temperature raises and then evaporates .