I think it is just a sponge?

[tanuki]

The red cactus looking guy maybe 5 inches long in the middle there. Is it just a whip red sponge or something? and the Yellow below it?

 

[smartorl]

Nice looking live rock. I am assuming the tank is relatively new, I bet you will continue to see all kinds of interesting things pop up.
The red does indeed look like a red tree sponge. Can you get a better photo of the yellow thing?

 

[bigarn]

Looks like you have a garden going on there ... i don't know though.

 

[tanuki]

This is probably as good as I can get without putting my camera in the tank. I can do that later if you want. I am just noticing that blue stuff too!

 

[teresaq]

yes they look like sponges. If they were exposed to the air, they may not make it though.
They are very pretty