Upside-down Jellyfish
Cassiopea andromeda
About
Turn this jellyfish over in your mind and you get its name: the upside-down jellyfish rests on the sea floor with its bell on the bottom and its frilly arms facing up, like a plant. Divers often swim right past it, mistaking it for a sea anemone stuck to the sand.
Also known as: mangrove upside-down jellyfish, Persian Gulf jellyfish
How to tell it apart
It is often mistaken for a sea anemone. The difference: it lies loose on the sand and pulses its bell gently, while an anemone stays fixed to rock or reef by a base and does not pulse.
Appearance
Its bell is yellow-brown with white or pale streaks and spots. It lies mouth-up on the bottom, with branching, frilled arms spread upward instead of trailing tentacles below it. The bell pulses steadily, drawing water through the arms.
Diet
It eats small animals, stunning them with stinging cells released in its mucus. It also gets food from algae living inside its tissue, which use sunlight to make energy that the jellyfish shares.
Did you know?
A small shrimp often lives among its arms, picking off parasites in exchange for shelter and protection.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.