Zooxanthellae (plural, ) are golden-brown intracellular endosymbionts of various marine animals and protozoa, especially anthozoans such as the scleractinian corals and the tropical sea anemone, Aiptasia. Most are autotrophs and provide the host with energy in the form of translocated reduced carbon compounds derived from photosynthesis. Zooxanthellae can provide up to 90% of a coral’s energy requirements. In return, the coral provides the zooxanthellae with protection, shelter, nutrient… (More on Zooxanthella)