Information specifically for A. ocellaris mating habits is not available, but general behavior believed to be typical of all anemonefishes is documented. They are territorial to the specific anemone they inhabit and are monogamous (Thresher 1984). Prior to spawning, nest preparation is done by the male, where substrate is cleared to make a nest on bare rock, but near enough to the anemone to still have protection from the overhanging tentacles (Thresher 1984). Males will attract the female by extending fins, biting, and chasing (Fautin and Allen 1992). During spawning, the males are increasingly aggressive. (Fautin and Allen, 1992; Thresher, 1984)
Amphiprion ocellaris is part of a the subfamily Amphiprioninae, or anemonefishes. This group is characterized by being protandrous hermaphrodites, meaning that all individuals develop first into males and then possibly into females later (Myers 1999). An adult male and female and several juveniles may reside together in an anemone. If the female were to be removed or die, the largest male would then become the female, with the larger of the immature fish transforming into a male. Females control males with aggressive dominance, thus controlling the creation of other females (Fricke and Fricke 1977). The largest male will in turn dominate the juveniles and prevents other males from spawning (Fricke and Fricke 1977).
Amphiprion ocellaris is able to breed nearly year round because it inhabits tropical waters (Thresher 1984) but may be somewhat limited in the northern reaches of its distribution during winter months. Spawning is concentrated around the full moon and usually occurs in the morning. Possible reasons for this include: stronger water currents for larval distribution, greater food supplies due to invertebrate spawning at the same time, and overall increased visibility (Thresher 1984).
When spawning is about to occur, the male will chase the female to the nest, but the female actually begins the process. The female makes several passes over the nest and eventually lays orange eggs over the period of 1-2 hours before leaving the nest (Thresher 1984). Eggs are approximately 3-4 mm in length and range in number from 100-1000 depending on the age of the fish (Fautin and Allen 1992). The male then continues the process as he passes over the eggs, fertilizing them. Eggs are attached to the substrate with a fine thread. Incubation is affected by water temperature, the cooler the water, the longer incubation period, but in general it requires 6-8 days before hatching occurs (Thresher 1984). The planktonic larval stage lasts from 8-12 days and ends when the juvenile fish settle returns to the bottom and attempt to find an anemone to inhabit. (Fautin and Allen, 1992; Fricke and Fricke, 1977; Myers, 1999; Thresher, 1984)
Prior to spawning, males prepare a nest where the eggs will be deposited. Males account for the majority of the egg care, but females are involved sporadically. Main duties include fanning the eggs and eating eggs that are infertile or damaged by fungus (Thresher 1984). Once the eggs hatch into the larval stage, they are independent of the parents. (Thresher, 1984)