Unknown polyp looking creature

[clcollins426]

Can someone ID these for me? We've had our tank up over a year but have been very cautious with adding fish and corals so we dont have a lot yet. I recently started adding reef roids to get our coral frags going and out of nowhere these things popped up and got big really fast. I want to make sure they are not harmful. I know of at least 4 in the tank. Any help is greatly appreciated!

 

[Highgrade]

Majano = bad

 

[Fudsey]

Aiptasia = Bad

 

[clcollins426]

What do they do and how do I get rid of them without hurting my fish and corals?

 

[clcollins426]

Majano = bad

What do they do?

 

[Highgrade]

What do they do and how do I get rid of them without hurting my fish and corals?

They spread quickly and can sting corals and fish. Get a Majano wand or you can try other products like Joe's juice/Aptaisia X

 

[JaimeAdams]

Just fully encapsulate them in super glue gel. Make sure to cover the whole thing so they don't send out any babies!

 

[DSC reef]

If you can remove the rock out of the tank I'd suggest doing that before removing or covering them. Less chance of spreading throughout the tank. Use a separate bucket of saltwater maybe during a water change.