[Subsea]

While I have not read anything about apples other than what Live Aquaria says. From my observation while keeping them healthy for two years, they feed on large particulate captured in the water column. I will see if I can find a video of an Apple feeding. It was pure synchronized choreography. With a row of arms surrounding mouth and extending out to end with capture small tentacles. When tentacles capture food, the signal to ingest, triggers the arm to bend inward to the mouth. Tentacles must be completely inserted in mouth triggering mouth closing as tentacles are withdrawn scraping off food from tentacles. As one arm is withdrawn the next arm is bending inward.