Also known as Colonial Ascidian, Compound Ascidian, Golden Sea Squirt, Robust Sea Squirt, Robust Tunicate, Sea Squirt, Soft Sea Squirt, Tunicate, Urn Ascidian, Urn Sea Squirt.
Found in colonies, anchored to dead corals and hard surfaces, in shallow sheltered waters.
They feed on detritus and plankton.
Length - 2.5cm
Depth - 1-20m
Widespread Indo-West Pacific
These urn shaped ascidians have numerous oral siphons.
Often confused with Didemnum molle which has numerous and minute oral siphons.
They vary in colour from white, orange to bright green.
The green colour inside is the result of being inhabited by minute blue/green algae.
The Egyptian sea star - Gomophia egyptiaca and the Sea Snail - Gyrineum gyrinum prey upon this sea squirt.
(edit) Ref: https://en.wikipedia.org/wiki/Atriolum_robustum