Spawning, eggs and larvae of the longnose filefish Oxymonacanthus longirostris, a monogamous coralivore

The longnose filefish (Monacanthidae, Oxymonacanthus longirostris ) was studied at a patch reef on Enewetak Atoll. Most of the larger adults formed monogamous pairs; the smaller fish were variously alone or in groups of 1-5 individuals who appeared to know one another. Only pairs having the largest males, on the periphery of the patch, were clearly territorial. Aggression was a common event featuring a few distinctive displays, most of which were used in courtship as well. Spawning may be a daily event, occurring around 1600 h. The female probes and selects a tuft of blue-green algae; the male nuzzles the female and they spawn in the algae.