"Paracorynactis hoplites" polyps will continually move their tentacles in an effort to detect prey. When an acrosphere comes in contact with suitable prey, it will immediately stick unto the prey's skin while firing its stinging cells (nematocysts). The polyp then extends itself towards the prey, bringing all the other remaining acrospheres towards the prey until it is trapped. The body can extend to five times its normal length when doing this. The polyp will then slowly pull the prey towards its mouth and digest it. Once the soft tissues are dissolved, the undigested pieces of the prey (e.g. spines) are regurgitated. Small prey are swallowed whole. Larger stiff-bodied prey, however, usually only get partially eaten before escaping by breaking the captured limb(s) off (autotomy). Captured large starfish, for example, usually only lose one arm. "Paracorynactis hoplites" are highly efficient predators of echinoderms. They specialize in preying on sea stars and short-spined sea urchins. They are also known to prey on sea cucumbers, brittle stars, and nudibranchs to a lesser extent, which indicates that they can potentially prey upon all soft-bodied slow-moving animals. They are also believed to supplement their diet with plankton when prey is scarce, as with other corallimorphs and sea anemones. But they will also refuse additional food once a prey has been recently captured and digested. Animals with smooth shells or long spines generally seem to be rejected as prey by "Paracorynactis hoplites" polyps. Among them are long-spined sea urchins like "Diadema setosum", "Diadema savignyi", and "Echinothrix calamaris". Brittle stars of the genus "Ophiomastix" as well as shelled gastropods are also not attacked. "Paracorynactis hoplites" is interesting for its ability to capture even large sea stars like horned sea stars ("Protoreaster nodosus") and the crown-of-thorns starfish ("Acanthaster planci"). Polyps in diameter have been observed capturing sea stars as large as across. "Paracorynactis hoplites" also do not seem to be affected by the toxins of venomous echinoderms like the aforementioned crown-of-thorns starfish and the flower urchin ("Toxopneustes pileolus"); both of which are toxic to humans, fish, and other marine predators.