Like crinoids, blastoids were high-level stalked suspension feeders (feeding mainly on planktonic organisms) that inhabited clear-to-silty, moderately agitated ocean waters from shelf to basin. The food gathering system of blastoids consisted of several types of ambulacra. Food entered the brachiolar ambulacra, was transferred to the side ambulacra through the brachiolar pit, then transferred to the main (median) ambulacra, and finally entered the mouth. Each of these ambulacra was roofed by cover plates. The cover plates of the brachiolar groove were movable and could open, allowing food to enter, or close as needed. Other cover plates may also have been movable.