Bythotiara depressa is a deep-water hydrozoan medusa (family Bythotiaridae) found in mesopelagic and bathypelagic oceanic zones worldwide, typically transparent and gelatinous with long trailing tentacles for capturing prey in the water column. The species plays important roles in deep-sea carbon cycling and food webs as part of the gelatinous zooplankton community. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.