The hydrozoan species Cladonema radiatum Dujardin, 1843 was found in an aquarium kept with seawater from the intertidal zone at Buleji (Karachi, Pakistan). The medusae were first seen on June, 03, 2016 and kept under laboratory conditions. They survived 74 days at room temperature 35°C, water temperature 33°C, salinity of 35-37‰ and pH 7.5-7.9. The species Cladonema radiatum is reported as a new record for Pakistan.