need some ID help

[dogmajones]

My brother has a weird red tube on the side of his live rock, most of the time it just looks deflated, but every so often it will suck some water in, and seconds later squirt it back out, can someone help me ID this?

 

[StevenBell]

Looks like a solitary tunicate-I believe Polycarpa aurata but could be wrong.

 

[Squishie89]

Sounds like and looks like a sea squirt/tunicate. They are filter feeders of micro-food. Can be hard to keep and may perish, but it is possible.