These guys are omnivorous, and may prey on invertebrates:
"Pherecardia striata apparently is chemically attracted to injured Acanthaster individuals and can be a significant source of their mortality by entering the body cavity through wounds made by other predators and consuming mostly soft tissues (Glynn 1984). In laboratory feeding trials P. striata showed strong preference for crustacean over Acanthaster remains, and gut contents included crustacean, polychaete, mollusc, and other unidentified animal tissue, and a few individuals examined were cannibalistic (Glynn 1984). Algae and detritus were found in greater frequency in gut contents than were animal remains, however, indicating a tendency toward omnivory (Glynn 1984)."*
*Source:
Diet of Worms Emended: An Update of Polychaete Feeding Guilds
www.academia.edu
