is a popular food in China, Japan, and Korea because of its fresh meat and high nutritional value. In recent years, desalination marine fish farming has aroused interest, and is a marine model organism for studying low-salinity aquaculture because of its ability to tolerate a wide range of environmental salinities. This fish species has been used to explore the molecular mechanisms of osmoregulation in marine teleosts due to its small genome, and>95% of the genome has been sequenced. Studies have shown that can survive in hypo-osmotic conditions such as 10%-25% saltwater, but the fish does not survive in freshwater. Therefore, to investigate the molecular mechanism of low-salinity tolerance in IgM), Na-K-Cl cotransporter 1 () was analyzed using real-time quantitative polymerase chain reaction (qRT-PCR) analysis of the gill and kidney from juvenile juveniles were divided randomly into five groups and maintained in water with salinities of 32 (control) 16, 12, 8, and 4 for 72 h. The results show that all three genes were expressed in gill and kidney. expression levels were not different between the two tissues ( expression level in the gill was significantly higher than that in the kidney ( expression decreased initially and then increased in the gill, whereas it decreased initially, increased, and finally tended to stabilize in the kidney in fish under acute low-salinity stress. More notable differences were detected in the gill between the low-salinity and control groups compared with those in the kidney at the same time points. expression decreased in the gill but increased in the kidney under low-salinity stress, and expression levels in the gill were higher at all time points than that at 0 h. expression levels in the gill of fish in the low-salinity groups were significantly lower than those in the control group at 6 and 72 h ( expression levels were observed in the low-salinity groups at 3 h, 6 h, 24 h, and 72 h compared with those in the control. Changes in kidney IgM, NKCC1, and T. rubripes were maintained in different salinities and for various durations. These results suggest that these three genes play an important role in the low-salinity tolerance of and provide basic data for clarifying the molecular mechanisms of osmoregulation in .