What is this sponge?

[saltyfish24]

My Petco was selling this piece of rock with a sponge on it, so I gave it a try. It's in QT tank and had a big bristle worm in the rock. Does anyone know what kind of sponge this is? Things I'm trying to find out:

• Is it photosynthetic?
• Is it possible to pop it off the rock and move it to my main tank?
• How can I propagate it?

I culture phyto, so I'm adding phyto to the QT tank for it to eat. I know some basics, like not letting it touch air and adding some silica to the water. But that's about it.

This same rock has some very white sponge inside it also. I'm guess that white sponge isn't photosynthetic, but I can't even take a good photo of it to ask questions about it.