SPAWNING BEHAVIOR AND EARLY ONTOGENY OF A POMACANTHID FISH, CHAETODONTOPLUS-DUBOULAYI, IN AN AQUARIUM

Spawning behavior of Chaetodontoplus duboulayi was recorded for the fi rst time in an aquarium. Dimorphic characters associated with sex were recognized in color pattern and caudal fin shape. From 14 March to 27 April 1992, a pair spawned almost daily. Spawning took place between about 50 min before and 70 min after the mercury lamps went out in the evening (18:40-20:40). A second spawning was observed on three evenin gs. The number of eggs per spawning ranged between 5,000 and 33,000. C ompared with the courtship of other pomacanthid species, the male's ra pid swimming, which was its only courtship display, and the female's a ctive display, including soaring and rapid swimming, were unique to C. duboulayi. Eggs were pelagic and spherical, 0.92-0.97 mm in diameter, and had a colorless transparent chorion and a yellowish transparent o il globule of 0.22-0.24 mm in diameter. Hatching occurred 24-25 hrs af ter spawning at 25.0-25.4-degrees-C. The newly-hatched larvae, 2.40-2. 63 mm in total length (TL) with 12 + 16 = 28 myomeres, had an elliptic yolk sac, which extended beyond the snout. The yolk was segmented. Th e oil globule was located at the rear end of the yolk sac. The larvae of C. duboulayi up to 48 hrs after hatching were generally similar to those of other pomacanthid species, but distinguishable by the pigment ation patterns.