Monogamous pair-bond formations between male and female individuals of Amphiprion percula are very strong and correlated with the small territory size that this species occupies. Despite being restricted to the immediate vicinity of its host anemone, Amphiprion percula can breed/spawn year round due to the perpetually warm tropical waters they inhabit.
Initiation of courtship is highly correlated with the lunar cycle. The moonlight serves to maintain a high level of alertness in the male, which then leads to increased social interaction with the female. Several days before spawning, the male will show morphological and behavioral changes: fin erection, chasing, nest preparation, and “signal jumping.” This last trait is depicted with rapid up and down swimming motions. Finally, extensions of anal, dorsal, and pelvic fins accompany the aggressiveness of the male (Fautin and Allen, 1992)
The choice of nest site is important for later survival of the eggs. It is usually located under the tentacles of the host anemone and securely positioned on a patch of cleared rock (Myers, 1999). The male has been known to nip at the bottom edges of the tentacles in order to cause retraction, and thus providing enough clearance to clean the area (Rosenberg and Cruz, 1988). Initially, the male clears algae and debris with its mouth only later to be joined by its mate (Fautin and Allen, 1992). There is clear emphasis, then, on male parental care, and this will be crucial when the eggs become vulnerable to predation.
Actual spawning procession takes place during the morning hours, and generally lasts about 30 minutes to more than two hours. At this stage, the conical ovipositor of the female becomes visible. Several eggs are extruded through this structure with each slow and deliberate pass as the belly gently brushes the nest surface. Following closely behind is her mate, who externally fertilizes the eggs as they are laid. The number of total passes during each spawning session is high, and the amount of deposited eggs range from 100 to over 1000, depending on fish size and previous experience. Older, more experienced mating pairs will produce more eggs. The eggs of Amphiprion percula are about 3-4 mm in length (Fautin and Allen, 1992).
After egg deposition has finished, the incubation period begins. At this time, the male actively mouths and fans the eggs, while simultaneously being on guard against any predators (Rosenberg and Cruz, 1988). Because the eggs are attached to the bottom substrate via adhesive strands, additional protection is provide by the overhanging tentacles of the host anemone (Allen, 1997). Removal of dead eggs and debris is also important in keeping a well-oxygenated nest and is accomplished by the male. The female, in contrast, is occupied with feeding during this time (Fautin and Allen, 1992). (Allen, 1997; Fautin and Allen, 1992; Myers, 1999; Rosenberg and Cruz, 1988)
- Allen, G. 1997. Marine Fishes of Tropical Australia and South-East Asia. Perth: Western Australian Museum.
- Fautin, D., G. Allen. 1992. Field Guide to Anemonefishes and their Host Sea Anemones. Perth: Western Australian Museum.
- Myers, R. 1999. Micronesian Reef Fishes. Guam: Coral Graphics.
- Rosenberg, S., G. Cruz. 1988. The anemonefishes of the Indo-Pacific. Sea Frontiers, 34: 16-21.