Cassiopea

Cassiopea (upside-down jellyfish) is a genus of true jellyfish in the family Cassiopeidae. They are found in warmer coastal regions around the world, including shallow mangrove swamps, mudflats, canals, and turtle grass flats in Florida, the Caribbean and Micronesia. The medusa usually lives upside-down on the sea floor in shallow areas, which has earned them their common name. They have a symbiotic relationship with photosynthetic dinoflagellates and therefore must lie upside-down in areas with sufficient light. Where found, there may be numerous individuals with varying shades of white, blue, green, and brown. They have distinctive methods of reproduction and prey capture, and are unusual in that they appear to sleep despite lacking a brain. They also have toxic proteins in their mucus.

== Species == According to the World Register of Marine Species, the genus includes 12 species: Cassiopea andromeda (Forsskål, 1775)—Indo-Pacific, introduced in the Mediterranean Cassiopea culionensis Light, 1914 Cassiopea depressa Haeckel, 1880—Western Indian Ocean off the African coast Cassiopea frondosa (Pallas, 1774)—Western Atlantic, Caribbean Sea Cassiopea maremetens Gershwin, Zeidler & Davie, 2010—Western Pacific Ocean, off the Australian Coast Cassiopea mayeri Gamero-Mora, Collins, Boco, Geson III & Morandini, 2022 Cassiopea medusa Light, 1914—Pacific Ocean, Philippines and Palau Region Cassiopea mertensi Brandt, 1838—Pacific Ocean Southern Micronesia Cassiopea ndrosia Agassiz & Mayer, 1899—Pacific Ocean, Australia and Fiji Cassiopea ornata Haeckel, 1880—Pacific Ocean, Palau, Philippines, Okinawa Cassiopea vanderhorsti Stiasny, 1924 Cassiopea xamachana Bigelow, 1892—Caribbean Sea and the Northern Atlantic Area of the West indies