Upside-down jellyfish
Cassiopea xamachana
Cassiopea xamachana, commonly known as the upside-down jellyfish, is a jellyfish that usually rests on the seafloor with its bell facing downward and its tentacles pointing upward.Its tentacles contain tiny algae that use sunlight to make food, helping support the jellyfish through a close partnership.
About this species
Species identity
Cassiopea xamachana, commonly known as the upside-down jellyfish, is a jellyfish that usually rests on the seafloor with its bell facing downward and its tentacles pointing upward.Its tentacles contain tiny algae that use sunlight to make food, helping support the jellyfish through a close partnership.
Where it lives
It lives in warm tropical and subtropical waters and it is commonly found in shallow coastal habitats such as lagoons, mangroves, seagrass beds, and sheltered bays. Because it relies partly on sunlight through its symbiotic algae, it prefers clear, shallow waters where light can easily reach the seafloor.
Role in the ecosystem
Its symbiotic algae turn sunlight into food, while the jellyfish also captures small animals with stinging cells. This combination links photosynthesis and predation in shallow coastal food webs and offers a clear example of how partnerships support marine life.
Scientific reference
Citation
Ocean Literacy Connections
This resource can be explored through Ocean biodiversity.
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FAQ
Why does Cassiopea xamachana lie upside down?
It rests with its tentacles facing upward so the tiny zooxanthella living inside its tissues can receive as much sunlight as possible for photosynthesis.
Can Cassiopea xamachana sting?
Yes, it has stinging cells on its tentacles that help it capture food and protect itself, although its sting is usually mild for most people.