While developing as larvae in the water column, individuals of this species consume smaller planktonic organisms. As an adult, this asteroid is an opportunistic carnivore, consuming sclerectinian corals, encrusting sessile invertebrates, and dead animals. It feeds by everting its stomach through its mouth onto its prey and digesting the tissues, absorbing the nutrients through the stomach wall. Acanthaster planci consumes most types of Indo-Pacific stony corals, such as Pocillopora, Acropora, Pavona, and Porites.

Animal Foods: cnidarians; other marine invertebrates

Plant Foods: algae

Primary Diet: carnivore (Eats other marine invertebrates, Scavenger ); herbivore (Algivore); detritivore