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Upside-down jellyfish (Cassiopea andromeda)

Photo of Upside-down jellyfish (Cassiopea andromeda)

Key facts

Scientific name
Cassiopea andromeda
Common name
Upside-down jellyfish
Category
Cnidarians
Family
Cassiopeidae
Genus
Cassiopea
Size
15–30 cm
Depth
0–10 m
IUCN status
Least concern (LC)
Danger level
Harmless
Habitats
seagrass, mangrove, sand
Behaviours
benthic, venomous
Ocean zones
Asian Pacific, Caribbean, Indian Ocean & Red Sea, Mediterranean, Eastern Pacific

Description

Cassiopea andromeda reaches 30 cm. Remarkable jellyfish living upside-down on substrate (bell below, tentacles up), unique behavior allowing to expose its symbiotic zooxanthellae to light (like a coral). Beige-brown-greenish color. Highly branched oral tentacles. Lives from 0 to 10 m in mangroves, calm lagoons, seagrass and shallow sands of Indo-Pacific and Red Sea, introduced Florida, Mediterranean, Hawaii. Listed LC. Stinging, causes dermatitis from released mucus (Cassiopea-itch). Unique photo subject for its anti-gravitational behavior.

Photo of Upside-down jellyfish

Photo of Upside-down jellyfish (Cassiopea andromeda)Photo of Upside-down jellyfish (Cassiopea andromeda)

Frequently asked questions

How big is the Upside-down jellyfish?
Upside-down jellyfish (Cassiopea andromeda) reaches 15–30 cm in length.
At what depth can you find the Upside-down jellyfish?
Upside-down jellyfish is found between 0–10 m deep.
Is the Upside-down jellyfish dangerous to divers?
Danger level: Harmless.
What is the conservation status of the Upside-down jellyfish?
IUCN status: Least concern (LC).
Where can you find the Upside-down jellyfish?
Found in: Asian Pacific, Caribbean, Indian Ocean & Red Sea, Mediterranean, Eastern Pacific.

Similar species

  • Cyanea capillata - Lion's mane jellyfish
  • Plumularia setacea - Feathery hydroid
  • Condylactis gigantea - Giant Caribbean anemone
  • Bartholomea annulata - Corkscrew anemone
  • Palythoa caribaeorum - Caribbean mat zoanthid
  • Zoanthus sociatus - Green sea mat

Sources

  • Taxonomy: WoRMS (AphiaID 135295)
  • Photos: iNaturalist (CC BY-NC)
  • Distribution: GBIF (taxonKey 2264603)
  • Conservation: IUCN Red List
  • Encyclopedia: Wikipedia