Can any tell me what this is?

[JustinGrr]

Hello,
I am new here and looking for some help. This just popped up in my reef tank that is just less than a year old. I am really hoping it's not a pest anemone.

 

[SeaCucumberFan]

Looks like aiptasia

 

[JohnnyHildo]

i'm going to disagree and say its an Majano Anemone which is no better. best to get rid of it asap.

 

[JustinGrr]

It was about half the size of a dime, do you think there are more? I took it out, luckily it was on a small piece of live rock.

 

[SeaCucumberFan]

Majano ≈ Aiptasia