Yellow Cup Coral (Tubastraea sp.)
The corals on the page are most likely Tubastraea coccinea ヒメイボヤギ and/or Tubastraea faulkneri イボヤギ. They are both Yellow Cup Corals that look much alike. I am not sure what the differences between them are. They both are found under ledges and have yellow to orange tenacles. They are about 1cm across.
