A paternity test based on microsatellite analysis of eggs under the parental care of a bourgeois male Pacific sergeant major, Abudefduf troschelii, included gametes from five females and two parasitic males. The nest area was monitored for five days to evaluate variation in reproductive success, and an approximately 300% increase occurred on the first and second days after new oviposition followed by a more than 300% reduction from the second to fifth days due to predation or filial cannibalism. Finally, the egg area on the last day corresponded to the initial nest area, suggesting selective care by the male.