This study evaluated the long-term growth of queen Holacanthus ciliaris maintained in a recirculating aquaculture system at LAPOM-UFSC over two years. Five pairs were monitored in 1,000 (3 pairs) or 2,000-L (2 pairs) tanks, under controlled conditions ( 27 ± 0.5°C, 34 ± 1‰, 14L:10D photoperiod) and fed 4x/daily. Sex was inferred from size dimorphism (males > females), although direct confirmation was not performed. Biometric monitoring included body weight (g) and total length (TL, cm), with weight-length ratio and Fulton’s condition factor (K = [100×Weight]/TL³) calculated. One 2,000-L tank included cohabitation with blue tang Paracanthurus hepatus (n=4) during the study; interspecific interactions were monitored.
Smaller individuals (presumed females) showed faster growth compared to larger ones (Fig. 1). Initial TL of females (5.97 cm) increased by 236% (20.08 cm, July 2025). The loss of juvenile coloration at ~15.9 cm TL (April 2024–January 2025) coincided with reduced growth, suggesting an energy reallocation toward gonadal maturation. Larger individuals presented higher K (2.57–2.58) than smaller ones (2.19–2.35), reflecting distinct growth/energy allocation patterns. The presumed males have not yet reached the maximum size reported for the species (~45 cm TL), indicating they still possess growth potential, although their slower growth rates may result from biological or environmental regulation, which should be further investigated.
In general, territorialism and intraspecific hierarchy, with occasional agonistic interactions, appear to be well tolerated by smaller individuals. Survival remained at 100% and no diseases were observed, confirming the species’ resilience in RAS. In coexistence with P. hepatus , a larger H. ciliaris suffered ocular trauma, leading to exophthalmos, with an unconfirmed cause, indicating the need for further studies on interspecific interactions.
These findings establish reference values for growth, condition factor and data for the onset of reproductive success of H. ciliaris in captivity, with the feasibility of maintaining reproductive pairs in 1,000 L systems. This study provides essential baseline data for developing and advancing in breeding protocols, reinforcing H. ciliaris as a promising candidate for ornamental aquaculture and conservation initiatives.