I'll go out on a limb and say it's an acropora. Definitely one of the species listed below. Unfortunately accurate identification involves killing a section of the coral and examining the skeleton under a microscope.
Acropora abrolhosensis
Acropora abrotanoides
Acropora aculeus
Acropora acuminata
Acropora akajimensis Veron, 1990
Acropora anthocercis (Brook, 1893)
Acropora arabensis Hodgson and Carpenter, 1996
Acropora aspera (Dana, 1846)
Acropora austera (Dana, 1846)
Acropora awi Wallace and Wolstenholme, 1998
Acropora azurea Veron and Wallace, 1984
Acropora batunai Wallace, 1997
Acropora bifurcata Nemenzo, 1971
Acropora branchi Riegl, 1995
Acropora brueggemanni (Brook, 1893) now classified as Isopora brueggemanni
Acropora bushyensis Veron and Wallace, 1984
Acropora cardenae Wells, 1986
Acropora carduus (Dana, 1846)
Acropora caroliniana Nemenzo, 1976
Acropora cerealis (Dana, 1846)
Acropora cervicornis (Lamarck, 1816) - staghorn coral
Acropora chesterfieldensis Veron and Wallace, 1984
Acropora clathrata (Brook, 1891)
Acropora convexa
Acropora cophodactyla (Brook, 1892)
Acropora copiosa Nemenzo, 1967
Acropora crassa (Milne-Edwards and Haime, 1860)
Acropora crateriformis (Gardiner, 1898) now classified as Isopora crateriformis
Acropora cuneata (Dana, 1846) now classified as Isopora cuneata
Acropora cymbicyathus (Brook)
Acropora cytherea (Dana, 1846)
Acropora danai (Milne-Edwards and Haime, 1860)
Acropora delicatula (Brook)
Acropora dendrum (Bassett-Smith, 1890)
Acropora derawaensis Wallace, 1997
Acropora desalwii Wallace, 1994
Acropora digitifera (Dana, 1846)
Acropora divaricata (Dana, 1846)
Acropora diversa (Brook)
Acropora donei Veron and Wallace, 1984
Acropora echinata (Dana, 1846)
Acropora elegans (Milne-Edwards and Haime, 1860)
Acropora elseyi (Brook, 1892)
Acropora eurystoma (Klunzinger, 1879)
Acropora exquisita Nemenzo, 1971
Acropora florida (Dana, 1846)
Acropora formosa (Dana, 1846)
Acropora gemmifera (Brook, 1892)
Acropora glauca (Brook, 1893)
Acropora globiceps (Dana, 1846)
Acropora grandis (Brook, 1892)
Acropora granulosa (Milne-Edwards and Haime, 1860)
Acropora halmaherae Wallace and Wolstenholme, 1998
Acropora hemprichii (Ehrenberg, 1834)
Acropora hoeksemai Wallace, 1997
Acropora horrida (Dana, 1846)
Acropora humilis (Dana, 1846)
Acropora hyacinthus (Dana, 1846)
Acropora indiana Wallace, 1994
Acropora indonesia Wallace, 1997
Acropora insignis Nemenzo, 1967
Acropora intermedia (Brook, 1891)
Acropora irregularis (Brook, 1892)
Acropora jacquelineae Wallace, 1994
Acropora kirstyae Veron and Wallace, 1984
Acropora kosurini Wallace, 1994
Acropora latistella (Brook, 1892)
Acropora listeri (Brook, 1893)
Acropora loisetteae Wallace, 1994
Acropora lokani Wallace, 1994
Acropora longicyathus (Milne-Edwards and Haime, 1860)
Acropora loripes (Brook, 1892)
Acropora lovelli Veron and Wallace, 1984
Acropora lutkeni Crossland, 1952
Acropora magnifica Nemenzo, 1971
Acropora microclados (Ehrenberg, 1834)
Acropora microphthalma (Verrill, 1869)
Acropora millepora (Ehrenberg, 1834)
Acropora mirabilis Quelch, 1886
Acropora monticulosa (Brueggemann, 1879)
Acropora mossambica Riegl, 1995
Acropora multiacuta Nemenzo, 1967
Acropora nana (Studer, 1878)
Acropora nasuta (Dana, 1846)
Acropora natalensis Riegl, 1995
Acropora nobilis (Dana, 1846)
Acropora ocellata (Klunzinger, 1879)
Acropora palifera (Lamarck, 1816) now classified as Isopora palifera
Acropora palmata (Lamarck, 1816) - elkhorn coral
Acropora palmerae Wells, 1954
Acropora paniculata Verrill, 1902
Acropora parilis Quelch, 1886
Acropora pharaonis (Milne-Edwards and Haime, 1860)
Acropora plumosa Wallace and Wolstenholme, 1998
Acropora pocilloporina Wallace, 1994
Acropora polystoma (Brook, 1891)
Acropora prolifera (Lamarck, 1816) - fused staghorn coral
Acropora pruinosa (Brook, 1893)
Acropora pulchra (Brook, 1891)
Acropora rambleri Bassett-Smith, 1890
Acropora reticulata (Brook, 1893)
Acropora robusta (Dana, 1846)
Acropora rosaria (Dana, 1846)
Acropora rudis (Rehberg, 1892)
Acropora russelli Wallace, 1994
Acropora sabulata (Dana, 1846)
Acropora samoensis (Brook, 1891)
Acropora sarmentosa (Brook, 1892)
Acropora schmitti Wells, 1950
Acropora secale (Studer, 1878)
Acropora sekiseiensis Veron, 1990
Acropora selago (Studer, 1878)
Acropora simplex Wallace and Wolstenholme, 1998
Acropora solitaryensis Veron and Wallace, 1984
Acropora sordiensis Riegl, 1995
Acropora spicifera (Dana, 1846)
Acropora splendida Nemonzo
Acropora squarrosa (Ehrenberg, 1834)
Acropora stoddarti Pillai and Scheer, 1976
Acropora striata (Verrill, 1866)
Acropora subglabra (Brook, 1891)
Acropora subulata (Dana, 1846)
Acropora suharsonoi Wallace, 1994
Acropora sukarnoi Wallace, 1997
Acropora surculosa (Dana, 1846)
Acropora tanegashimensi -s Veron, 1990
Acropora tenella (Brook, 1892)
Acropora tenuis (Dana, 1846)
Acropora teres (Verrill, 1866)
Acropora togianensis Wallace, 1997 now classified as Isopora togianensis
Acropora torihalimeda Wallace, 1994
Acropora tortuosa (Dana, 1846)
Acropora tumida Verrill, 1866
Acropora turaki Wallace, 1994
Acropora valenciennesi (Milne-Edwards and Haime, 1860)
Acropora valida (Dana, 1846)
Acropora variabilis (Klunzinger, 1879)
Acropora vaughani Wells, 1954
Acropora vennoveter Venson and Veterline, 2007
Acropora verweyi Veron and Wallace, 1984
Acropora wallacea Veron, 1990
Acropora willisae Veron and Wallace, 1984
Acropora yongei Veron and Wallace, 1984
