The freshwater hydrozoan Craspedacusta sowerbii has invaded exotic habitats around the world. This data set contains information on the water and organic content, as well as elemental composition (carbon, nitrogen, phosphorus) of jellyfish sampled in Canada and the USA in August and September 2021. Specimens (N = 1385) were collected from eight lakes in British Columbia and one lake in Virginia using dip net, cast net, and jars from near the surface (top 1 m). Jellyfish were sexed based on light microscopic observation of their gametes. Specimens collected from British Columbia were exclusively male, whereas specimens from Virginia were identified as females.