Kind of interesting looking, but...

[rulerof5]

This blue sponge type growth has been growing around my cabbage leather. I noticed tonight that it actually has clear tubes in it (for water suction, feeding?). I do not know what it is. My cabbage is growing since I moved it to another spot in my tank. My water parameters are all in the proper zones...does anyone know what this blue growth is?

 

[Reefing Madness]

Just looks like a sponge.

 

[NanaReefer]

Definitely a sponge. Awesome color! Those tubes are called siphons and yes they are used for drawing/expelling water which they filter to feed.

 

[rulerof5]

It seems to get along with my cabbage and nothing else in the tank is bothering it, so I guess I am the proud owner of a blue sponge Thanks for the input!

 

[sageharmon]

That is a rare deep water blue sponge I think!!