Purple Tube Like Growth

I have had this Fiji rock for a couple weeks and there is a ton of different things growing out of it. The neatest thing I have found is this growth of what looks like a bunch of purple tubes. Anyone have an idea what this is? It is small so I tried to center it in the picture you have to magnify it to see it.

 

Perhaps Foraminiferans, here is a link to assist you with common hitch hikers.


Live Rock Hitch Hikers

 

vetrimid (spelling) snail. Catch food particles with a mucus strand, kind of like a net. Numbers increase with available nutrients, typically a nuisance in large numbers as the "nets" irritate corals. Some species of wrasse eat them. Hermit crabs like to destroy the tubes, but not eat the snail I've found.

EDIT:After reading Coralline's post, I see possible formaniferans too.

 

I have attached a cropped close up. I searched the two possibilities you gave me and it does not look like either one of them.

 

In the very center, down and to the right of the reddish things? that's the osculum of a sponge.

(those reddish things are the formaniferans Coralline was talking about(I think) )

 

Thanks, I wonder how big it will get?

 

FWIW, the osculum will stay the same size, but the sponge itself will grow indefinitely. I have one that is the started as a little hitch-hiker and now covers a whole rock (softball size).