Spawning behavior of Centropyge, Dwarf angelfish, pygmy angels

The spawning behavior of Centropyge was nearly identical in all species studied and also showed great similarity between aquarium and reef settings. Spawning occurred at the conclusion of an intricate courtship which was repeated with great regularity each evening- The following generalized account summarizes our observations:

In our field studies, as evening approaches with the sun just above the horizon there is a subtle change from casual roaming and preoccupation with grazing, to an increasing group awareness and interaction.

Female Station - Each female becomes stationed near her own coral prominence, the same one each evening, and remains in or around this shelter, which is located within the group spawning territory.

Male Patrolling - The male begins a methodical and repetitive patrolling of the spawning territory, precisely retracing his path on each round at 2-6 minute intervals. Agnostic encounters with other species within the territory are seen commonly. In our laboratory studies patrolling was not discernible with in the limited confines of the aquariurm.

Courtship consists of the elaborate rituals of the prespawning male-female interactions and was identical in the field and aquarium.

Visitation - The patrolling male visits each female station sequentially on each round, makes a deliberate search for the female on or inside her coral, and engages in brief courtship gestures which increase in intensity and duration on each round.

Approach - Meet - Grunt. - As the male approaches a female station, the female often emerges from her coral shelter, as if signaled by the approaching male, and swims out to meet him. In the aquarium, a chirping grunt is audible ( particularly in C. flavissimus ) as the male approaches the female. Because of the females awareness of the approaching male a similar signal is suspected during reef approaches.

Circling - As the male approaches a female station , he excellerates his swimming tempo to an impulsive circling around the female, as if spinning on a string. His body is curved and there is a full fan-like erection of unpaired fins, maxirnallv increasing the concave lateral body surface presented to the female. Later in courtship the female may also participate and both may engage in head-to-tail circling.

Female Follow - After a brief courtship encounter, the male continues on his rounds and the female often follows part or rarely all the way to the next female station or a coral prominence. Simultaneous courtship play with two or three females may then be seen and an occasional early spawning attempt with one female may be interrupted by agnostic interference by another female.

Quiver Display - As. the male repeatedly returns to a female station, courtship intensifies on each visit. Bursts of circling by the male are interrupted by sudden stops; paired fins perform a nonpropulsive flutter, the entire body quivers and blanches and unpaired fins are fully flared.

Flutter Rise - After several male visits and courtship encounters, the female eventually indicates willingness to spawn by ascending over her coral with non-propulsive fin flutter, body quiver and blanching, and full erection of unpaired fins.

Blanching - The posterolateral body surface brightens as the color intensity fades. Blanching is more marked in the male during courtship. Female blanching is greatest during the flutter rise and indicates her readiness to spawn. Some blanching was noticeable in all species studied; in uniformly colored fishes, such as the dark blue C. argi, dark reddish brown C. fisheri and deep blue C. acanthops, the body sides blanch to a grayish hue; the deep yellow C. flavissimus fades to near white. The dark blue and red banded C. bispinosus fades its blue bars converting the dark blue-red body sides to a pale red; in the deep red and black banded C. loriculus the red fades to orange These color changes may vary rapidly and are most noticeable under the aquarium lights; but even in the reef light the body sides of C. argi blanch visibly.

Spawning Posture - There is a characteristic alignment of spawning partners with the male in an oblique (45 degree) head up position, its snout nuzzled against the posterolateral body side of the female just dorsad to the genital orifice, at an area overlying the ovary. The female is horizontal or slightly tilted, head down.

Spawn Rise - Maintaining this configuration, the spawning pair rises gradually in the water column some 10 30 cm as both partners display, vigorous fin flutter and body quiver: the pectoral fins of the female are erected strongly downward. The male appears to push upwards against the female tilting her slightly head down. Most initial spawning rises are brief and dissolve gently after a 5 - 15 cm rise as the partners drift out of alignment. Occasionally a bulging egg mass is seen to protrude from the female cloaca on each of the last few spawning rises, just before egg discharge.

Thrust and Turn - Egg discharge is, initiated by an abrupt forceful thrust by the male snout against the female abdomen as if attempting to express eggs from the ovary. The male then executes a split-second reversal of its body axis swinging its head sharply downward and flinging its curved posterior body up against the side of the female. This lightning-speed action approximates the genital orifices of the mating partners for a fleeting instant when sperm discharge results in mixing of released gametes for fertilization.

Break and Retire - With gamete release the spawning posture is suddenly disrupted as both partners forcefully dart towards substrate. T male having swung its head downward during the spawning flip is usually in the lead and is followed by the female which occasionally delivers a rapid nip to the male as they dart for shelter. The female hides in her coral and becomes unresponsive to further male courtship advances; the male patrols his territory for a short period after all females have spawned until he retires as darkness prevails.

The left photo shows a pair C. flavissimus in the "Spawning Posture".
The right photo shows a pair of C. resplendens just prior to "Thrust and Turn".