Aquaporins (AQPs) are specialized membrane proteins that create selective water channels, facilitating the transport of water across cell membranes and playing a vital role in maintaining water balance and regulating osmotic pressure in aquatic animals. This study identified 9 aquaporin genes from the genome of R. philippinarum, and a comprehensive analysis was conducted on their gene structure, phylogenetic relationships, protein structure, and chromosome localization. RNA-seq data analysis revealed that aquaporin genes were differentially expressed at different developmental stages, in tissue distribution, and in response to salinity stress. In addition, qPCR results revealed that the expression levels of aquaporin genes (AQP1, AQP4d, and AQP3) were significantly elevated in response to both acute low and high salinity stress, suggesting their important role in osmotic pressure regulation in R. philippinarum. This study's results offer an important reference for further investigations into the regulation of osmotic pressure and salinity adaptation of aquaporin in R. philippinarum.