What is this growing on my Reef?

[TornadoFlipN]

I recently starting my tank and noticed this growing from one of my rocks. What is it, good/bad? Thanks in advance.

 

[DMG Reef]

If it retracts into a hard tube when you touch it, it's most likely a fan worm. But if it has no tube but retracts into the rock, it could be aiptasia.

Fan worm = good.
Aiptasia = very, very bad.

A clearer pic would help.

 

[Auquanut]

If it retracts into a hard tube when you touch it, it's most likely a fan worm. But if it has no tube but retracts into the rock, it could be aiptasia.

Fan worm = good.
Aiptasia = very, very bad.

A clearer pic would help.

I agree. Looks like some kind of fan worm. Couldn't hurt to give it a little poke.

 

[TornadoFlipN]

If it retracts into a hard tube when you touch it, it's most likely a fan worm. But if it has no tube but retracts into the rock, it could be aiptasia.

Fan worm = good.
Aiptasia = very, very bad.

A clearer pic would help.

I tried to touch it but it sunk back into the rock with a hard tube. So most definitely a fan worm, thanks.