Sea cucumber collects food by extending its tentacles surrounding its mouth. The type of tentacle is closely linked to the mode of feeding employed by each species [6]. For example, holothurians, Psychropotes longicauda have stubby peltate tentacles that collect sediment particles by sweeping, whereas holothurians, Oneirophanta mutabilis have branched digitate tentacles that collect sediment particles by raking [7]. The tentacle structure and feeding strategy vary not only in different species but also within same species. Cameron and Fankboner [8] observed that the pentacula larva, juvenile, and adult life stages of Parastichopus californicus had subtle differences in tentacle structure and feeding strategy. In the present study, we firstly investigated the mechanisms of locomotion and food capture in different size groups of A. japonicus at the tentacle level through real-time photography