Tiaropsis multicirrata is a leptomedusa hydrozoan (family Eirenidae, order Leptothecata) found in cold temperate to boreal coastal waters of the North Pacific and North Atlantic, a transparent, disk-shaped hydromedusa with numerous evenly spaced tentacles around the bell margin and clusters of statocysts for orientation in the water column. The species is a planktonic predator of small copepods and other zooplankton, and its transparent body and relative abundance make it a tractable subject for laboratory studies of hydrozoan medusa physiology. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.