What is in my live rock?

[AlishaSkye]

I bought a live rock and I want to know what is growing/living there.

[vikubz]

Looks like a ball anemone to me. Pretty common.

[danil]

it does look like Aiptasia. Bad thingy. I would use Aiptaisa X to kill it... just get second opinion on it.

[Stevenliu9]

Not aptasia. Just a common anemone. Like Vikubz said, pretty common, I've had those in my tank/sump and they never cause trouble, never grow, never spread.

[Sugar Magnolia]

Yes, ball anemone. Generally harmless.