I'm new here and this is my first post. I set my tank up with live rock from my lfs a couple of weeks ago. This evening I noticed this thing sticking out. Is it Aiptasia? Or some other pest anemone?
Yes, and it looks like there are a few more lurking to the right of that one. You might want to add a peppermint shrimp to the set up after it cycles. Welcome to R2R.