These are small jellyfish that can swim, but which also fasten to the substrate. Unlike the Staurocladia mentioned above, they don't crawl much. Not much is known about their biology. In aquaria they probably feed on small copepods and particulate material in the water. They may be distinguished from Staurocladia by more developed gobular bell, their slightly larger size, and the shape of the tentacles.
- courtesy of Mark Li, of a Cladonema species in an aquarium.