This topsy turvy jellyfish can be seasonally common on Pulau Semakau,
found throughout the intertidal from the seagrass meadows to the reef
Bell about 4-12cm, with short stout branched oral arms. The oral arm
length about half the diameter of the bell. There is usually a pattern
of white bars on the upper and underside of the bell.
The animal prefers to be 'upside down', with its bell facing the sea
floor and oral arms facing upwards toward the light. When one is turned
the 'right' way up, it will slowly turn itself upside down again.
In its preferred position, with only its oral arms visible and bell
hidden, it is sometimes mistaken for a sea anemone.
The jellyfish harbours
microscopic, single-celled algae (called zooxanthellae) inside its
body. The algae undergo photosynthesis to produce food from sunlight.
The food produced is shared with the jellyfish, which in return provides
the algae with shelter and minerals. It is the algae which gives the
jellyfish its colours. Because it relies on photosynthesis,
the jellyfish tends to be found in shallow waters.
Pulau Semakau, Mar 08
Pulau Semakau, Nov 07
Terumbu Semakau, Nov 12
jellyfishes on Singapore shores
With grateful thanks to Dr
Michael N Dawson of the University of California, Merced for identification
of this jellyfish.