Finger-licking good. Our Sea Cucumber is enjoying an afternoon snack in the Tide Tank. Sea Cucumbers are Echinoderms (the same phylum as seastars). What look like arms and fingers are actually tentacles. Diet consists of plankton and decaying organic matter. Yummm. The video is of a birds-eye view of our sea cumcumer with light pink tentacles streched outwards, grasping at floating debris. The tentacles are folding inwards and the ends are going into the mouth like structure of the sea cucumber.