Is this an anemone? A worm?

[gareefer1029]

This just showed up recently attached to the back wall of my QT tank. It is about the size of a dime. Any idea what this is? The arms move around a bit (front and side shots included).

 

[Viva'sReef]

Welcome to R2R!! That is your enemy. It is Aptasia and they will spread like wildfire if not removed or killed

 

[Gernader]

+1 to aiptasia. It is considered as a pest

 

[gareefer1029]

Will this hurt my fish? This is a fish only QT, so no too worried about Corals.

 

[SHNICI]

Aiptasia read the thread if you wish , can be very useful for you now, or in the future @gareefer1029