Nice coral. Love the colors.
While you may have had some sort of broadcast spawning event (cloudy water) from some coral, it did not result in the small new polyp visible there. Polyps like that form by budding - asexual reproduction - new identical genetic copy of original. Broadcast spawning is sexual reproduction, gametes expelled to be combined with gametes from other members of the same specie to form new individuals with genes from both the contributing parents.