Yellow sea squirt

Scientific name : Phallusia julinea

Large ascidian (up to 30 cm), bright yellow colour. Siphon's edge indented.
Often living hidden in a sponge or a coral, or under a rock, with only the siphons appearing. Common on reef front and external reef.
Confusion is possible with other yellow coloured large ascidians, like Ascidia sp. 2 (yellow form) or Ascidia sp. 4. The indented siphon is a good diagnostic.
The tunic is always clean from epibiotic organisms, due to a natural anti-fouling.

Associated organisms
With massive sponges and corals.