White Cluster Growth on Zoa Polyp

[ariellemermaid]

I’m wondering if anyone can ID this white (not the color it appears in the photo) cluster growth on the side of one of our zoa polyps. It’s solid white and in a circular formation. The edges are made of these little tube things with a hole in the middle of each. Doesn’t seem to be bothering the polyp at the moment.

 

[NowGlazeIT]

Bump

 

[JGT]

Appears to be a sponge.

 

[Goaway]

colonial tunicates. They could suffocate the coral. Or die off.