Captive breeding of the Queensland yellowtail angelfish, Chaetodontoplus meredithi (Kuiter, 1990): Spawning, early ontogeny, larval rearing, and temperature-salinity impacts on hatching and survival

The Queensland yellowtail angelfish, Chaetodontoplus meredithi , an economically and ecologically significant marine ornamental species endemic to Australia's eastern coast, has been the subject of limited research on its reproduction and larval development. This study offers the first comprehensive account of natural spawning, early developmental stages, larval rearing, and optimal rearing conditions for the species. Between August 2018 and September 2019, a captive adult pair exhibited year-round spawning, producing 161 spawns over 426 days. Spawning frequency increased significantly with rising water temperatures, showed no significant association with salinity, and exhibited no correlation with lunar phases. Fertilization success was achieved in 87.6 % ± 14.2 % of spawns, with a median fecundity of 2011 eggs per spawn. The fertilized eggs were spherical, transparent, pelagic (0.87 ± 0.02 mm in diameter), and hatched within 15 h at 26.0 °C. Newly hatched larvae measured 2.52 ± 0.08 mm in total length (TL). By 3 days post-hatch (dph), the larvae had grown to 3.02 ± 0.10 mm TL, the yolk sac was completely resorbed, and they had begun exogenous feeding on S-type rotifers and copepod nauplii. Juveniles emerged by 48 dph, averaging 18.09 ± 1.17 mm TL, and demonstrated territorial behaviour. The water quality conditions that resulted in the highest hatch rate and survival activity indices (SAI) were determined to be a salinity of 33 psu and a temperature of 27 °C. These findings expand understanding of Queensland yellowtail angelfish reproduction, supporting captive breeding, larval rearing, sustainable aquaculture, and efforts to mitigate overfishing from the marine ornamental trade. • The natural spawning and early development of Chaetodontoplus meredithi is reported. • A combination of S-type rotifers and copepod nauplii was used at first feeding. • The optimal conditions for egg incubation and larval rearing were 27 °C and 33 psu. • These findings advance captive breeding and sustainable aquaculture for C. meredithi .