The Upside-down Jellyfish (Cassiopea xamachana) is known for its unique posture—resting upside down on the seafloor. It lives in shallow tropical waters and maintains a symbiotic relationship with photosynthetic algae.
Scientific Name
Cassiopea xamachana
Habitat
Warm, shallow coastal waters, mangrove swamps, seagrass beds, and coral reefs, especially in the Caribbean, Florida, and the Indo-Pacific.
Conservation
Not endangered; important as ecological indicators in mangrove and reef ecosystems.
Lifespan
Typically ranges between 1 to 2 years in the wild.
Fun Fact
Upside-down Jellyfish rest on their bell and have a mild sting, but they are more known for their algae partnership than for stinging.
Diet
Zooplankton and nutrients from symbiotic algae (zooxanthellae) via photosynthesis.
Average Size
Can grow up to 30 cm (12 inches) in diameter.
Location / Placement info
Displayed in the Coastal Reef Exhibit, near the Ocean-View Tunnel
FAQ
What is the lifespan of the Upside-down Jellyfish?
Upside-down Jellyfish typically live up to 1–2 years in captivity, depending on water quality and lighting.
What do Upside-down Jellyfish eat?
They rely on symbiotic algae for most nutrition but also absorb plankton and nutrients from the water.
Are Upside-down Jellyfish aggressive?
No, they are non-aggressive and pose little threat, though they can mildly sting if touched.
What is the ideal tank size for Upside-down Jellyfish?
A shallow tank of at least 30 gallons with low flow is ideal to mimic their natural habitat.
Do Upside-down Jellyfish need a reef environment to survive?
Not necessarily, but they thrive in tanks with sand beds, light exposure, and calm conditions.
How big do Upside-down Jellyfish grow?
They can grow up to 10–12 inches (25–30 cm) in diameter.
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