Sanderia malayensis is a species from the phylum Cnidaria, class Scyphozoa, and order Semaeostomeae, found in tropical waters, including the Red Sea, Indian Ocean, and Malaysian waters. Its distribution extends to the waters of Australia and Japan. This study aimed to evaluate the effects of salinity on the growth and survival of Sanderia malayensis ephyrae and to determine its optimal salinity range. The experimental design included two temperature conditions (20 °C and 24 °C) and three salinity levels (21 PSU, 24 PSU, and 27 PSU). The results indicated that growth and feeding abilities were significantly higher in 24 PSU and 27 PSU environments compared to 21 PSU, with the best results observed at both temperatures. Survival rates were higher at 24 PSU (20 °C: 90%, 24 °C: 79%) and 27 PSU (20 °C: 87%, 24 °C: 86%) compared to 21 PSU (20 °C: 70%, 24 °C: 55%). Despite lower survival at 21 PSU, the species demonstrated wide environmental adaptability. These findings suggest that Sanderia malayensis ephyrae are highly adaptable to varying salinity conditions, indicating the potential for the species to expand its distribution into South Korean waters and other East Asian marine ecosystems, including China and Japan, which are impacted by climate change.