See the RC article by Eric Borneman and/or Advanced Aquarist's Online Magazine, 2003 article which describes zoanthid and protopalythoa spawning events. The later article describes zoanthid spawning synchronized with classic coral spawning events on the Great Barrier Reef. Beside the classic matting and budding of new polyps, they can actually spawn like SPS. Borneman's article has some great pictures. Cook, can you possible get some better pics if it is still occurring or occurrs again?