Coral bleaching

I think coral bleaching is like this: the algae (zooxanthellae) is inside the cells of the coral and under its control. Stress due to high temperature, fresh water or disease prevents the cells from controlling the algae so the algae escapes (zooxanthellae can swim).

When the algae and its associated pigments leave, the flesh of coral is see-through (like their jellyfish cousins) and the white skeleton is visible.

Coral is still alive after bleaching and it will digest its own skin to survive and if the stress disappears and if it can capture (swallow) more algae it might.