Reproductive aspects of native and endangered wild Betta fish (Betta dennisyongi and Betta rubra) from Aceh waters, Indonesia

Betta dennisyongi and Betta rubra are ornamental fish native to Aceh waters, facing a decline in population due to overexploitation and environmental changes. Therefore, this research aimed to obtain information regarding the reproduction of B. dennisyongi and B. rubra. The study was conducted from January to December 2020, with B. dennisyongi and B. rubra samples collected from Nagan Raya Regency and Aceh Besar, respectively. Approximately 1,099 Betta fish samples were successfully collected, comprising 600 B. dennisyongi and 499 B. rubra. The results showed that sex ratio (male:female) analysis had 1:5 and 1:6 for B. dennisyongi and B. rubra, respectively, indicating a predominance of female. Further analysis showed that only 15% of female B. dennisyongi samples had mature gonads out of 505 and 3.7% of male among 95 B. dennisyongi. Female of B. dennisyongi showed first mature gonads at a size of 3.86 cm, while male had maturity at 3.99 cm. For B. rubra, only 11.1% of female and 26.9% of male samples showed mature gonads out of 432 and 67, respectively. Female of B. rubra first matured gonads at a size of 3.86 cm, while male had maturity at 3.90 cm. Reproductive analysis showed that both species were continuous spawners in the year, as indicated by mature gonads in each month of observation, with fluctuating percentages. The peak spawning period for B. dennisyongi occurred in October, while B. rubra was observed in January. Consequently, it was recommended not to catch these species during their spawning months to maintain the sustainability of these endangered species.