A total of 38 S. formosus samples (including golden arowana, green arowana and red arowana), collected from Southeast Asia, and their sample codes and GenBank™ accession numbers are listed in Table 1. All the samples used in this analysis were obtained from either other investigators or our lab and were cultured after being legally imported from Malaysia to our lab. All the fin clips collected were obtained and fixed in 95% ethanol and stored at −20 °C. Total genomic DNA was extracted using the OMEGA E.Z.N.A Tissue DNA Kit according to the manufacturer's protocol.