Looks just like the photo of octobubble in Eric Borneman's book A Practical Guide to Corals. It lists other possible names as bladder, bubble and pearl. Scientific name Plerogyra flexuosa.
It adds that feeding most stony corals is not necessary, although many will accept small pieces of food, such as bits of shellfish, crustaceans, squid, and even fish. Other ahermatypic (or zooxanthellae lacking) corals require feedings for their survival.
HTH