The lost of color or “bleaching” is a result of the loss of an anemone’s zooxanthellae. This can happen for a number of reasons such as excessive temperature changes, excessive lighting, insufficient lightning, physical stress, excessive salinity, etc.
Just like corals, anemones use their zooxanthellae to feed on light. The other part of their nutrition comes from meat. Unfortunately, they cannot survive solely on captured prey as their primary source of energy. An anemone without zooxanthellae is usually on the brink of death so: