| Species name | Common name | Distribution | Max. Length (cm) |
|---|---|---|---|
| Obelia austrogeorgiae Jäderholm, 1905 |
Antarctic Atlantic | ||
| Obelia bidentata Clark, 1875 |
Doubletoothed hydroid | Antarctic, Atlantic, Pacific and Arctic Oceans | |
| Obelia dichotoma (Linnaeus, 1758) |
Sea thread hydroid | Arctic, Atlantic, Indo-Pacific | |
| Obelia fimbriata (Dalyell, 1848) |
Northeast Atlantic | ||
| Obelia geniculata (Linnaeus, 1758) |
Knotted thread hydroid | Indo-Pacific, Atlantic Ocean, Antarctic, and the Arctic | |
| Obelia longissima (Pallas, 1766) |
Cosmopolitan | ||
| Obelia multidentata Fraser, 1914 |
Eastern Pacific | ||
| Obelia plicata Hincks, 1868 |
Atlantic, Pacific and Arctic Oceans | ||
| Obelia racemosa Fraser, 1941 |
Western Atlantic |