The main carbon requirements of Acropora millepora are fulfilled by their symbiosis with unicellular algae (Anthony, 1999). Dinoflagellates, such as zooxanthellae, line the gastrovascular cavity of corals and contribute their photosynthetic products to the coral.

However, many studies have shown that hermatypic corals are able to capture and ingest particulate food from varied sources, including phytoplankton, zooplankton, and bacteria. Usually, this species extends its polyps during both the day and night (something that is uncommon among coral) (Anthony, 1999).

Coral also has the ability to be a suspension feeder. Usually, we think of fine suspended particulate matter (SPM) in high concentrations to be a stress on nearshore coral reefs. Because coral is able to be a passive suspension feeder, SPM can actually serve as a food source (Anthony, 1999). Various sources of SPM include suspended sediment, detrital matter, excretory products from other animals, and coral mucus (Anthony, 1999). These particles are also exposed to colonization by macroalgae and bacteria, which makes this a more organically valuable food source. The contribution of zooplankton feeding is not all that different from SPM feeding, in terms of maximum rate of SPM carbon assimilation. Also, when particle concentration is high, SPM feeding can cover half of the carbon and one-third of the nitrogen that is necessary for coralline tissue growth. As SPM concentrations increase, Acropora millepora ingestion rates increase linearly (Anthony, 1999). Successfully capturing and ingesting fine particles only increases 1-fold for every 8-fold increase in food availability (Anthony, 1999).

Animal Foods: zooplankton

Plant Foods: phytoplankton

Other Foods: detritus ; microbes

Foraging Behavior: filter-feeding

Primary Diet: herbivore (Eats sap or other plant foods); planktivore