Why does coral have creatures that make chlorophyll but don't photosynthesize?

(Natural News) What do you call a tiny critter that lives in most corals and creates chlorophyll but doesn’t bother using it to turn sunlight into energy? Dubbed corallicolid, this unusual creature is the first known organism that is capable of phototropic behavior yet doesn’t perform photosynthesis. Corallicolids belong to the phylum Apicomplexa. Its relatives...