Help ID 2 things in my tank...

Just curious whats this sponge like substance growing out of one of my rocks and also another thin twig like thing..




and the twig thing:

 

Not sure what either is but look like common growths and should not be harmful.

 

Not sure on the first. Picture isn't too clear. Could just be a sponge there are about a billion types.

The second one appears to be the tube of some sort of tube worm. Could be a spionid worm, a feather duster, or a vermitid snail. Could tell you which without seeing what comes out of the tube. I have all three in my tank and the feather dusters are the only thing worth having around if its a reef tank.

 

Stepho: Any ideas as to how long it takes a worm or featherduster to appear out of these tubes?... I'm a complete newbie so it may be a stupid question to ask.

 

The first looks like a type of encrusting sponge. Harmless filter feeder. If you have or add tangs or pigmy angels, you'll see them nibble on it occasionally.

A friend of mine had something that looked quite similar appear in his reef tank. We weren't sure what it was for a while. He ended up with several of them over a period of 4 to 5 weeks before we finally saw the feather dusters popping out of the tubes.

Hope this helps.

P.S. The only stupid question is the one that's left unasked.