Abstract
Spawning behavior and early life history of Chaetodon nippon Steindachner et Döderlein are described in detail from aquarium observations.The early life history of the present species is the first record among the family Chaetodontidae.Spawning of C. nippon occurs between multiple males and one female in the early hours of the night in March, August, September, and October at water temperatures of 23°C or higher.Fertilized eggs are buoyant, spherical, and colorless.They measure 0.70-0.74 mm in diameter and contain a single oil globule.Hatching takes place 28 hrs.10 min.after fertilization at water temperatures of 22.2-23.7°C.Newly hatched larvae measure 1.45-1.53 mm in total length and have a large ovoid yolk.An oil globule is situated at the rear of the yolk.Early larval stages of C. nippon are described for the first three days after hatching.The mode of reproduction and the characteristics of developing eggs and larval stages of this species are compared with those of allied fishes previously studied.
