Their growth is dependent upon diet, temperature and salinity. Bloodworms are most abundant in the middle portion of the tidal flats. They feed on marine worms, mollusks and other invertebrates while burrowing through mud or sand. In comparison to some other polychaetes, bloodworms are poor swimmers. However, they are excellent burrowers using their conical prostomium or lip, stiff parapodia, and peristaltic motion.
Bloodworms sense through the use of tactile cells which are primarily located in their head area.
An anterior brain receives impulses from a large ventral nerve cord, that runs from the anterior to the posterior end of the worm. Bloodworms have separate sexes. Spawning is initiated during the middle of June, just prior to high tide. Water temperature is critical for spawning to occur. Suitable temperatures range from 55 degrees to 57 degrees Fahrenheit.