Harmless
Rhizostoma octopus
Scyphozoa (Rhizostomatidae)
One of the largest jellyfish in Europe. Despite its impressive size, it often shelters small juvenile fish that come to hide under its umbrella to protect themselves from predators.
Sting symptoms
Generally harmless, but the mucus released in the water around it can be slightly irritating.
Identification
Massive, white to bluish bell-shaped, often with a blue or purple edge. It has no long tentacles but very large, folded oral arms resembling a cauliflower.
Size
Umbrella: up to 90 cm (very massive)
Habitat
Coastal zones and estuaries.
Scientific family
Scyphozoa (Rhizostomatidae)
Community photos
Photos submitted and verified by Meduseo users.
23/03/2026
Arcachon