We just happened to buy a rock flower nem at our LFS last week!- it came in as a hitch hiker on some coral. I couldn't get a good picture of it because it's decided to set up shop BEHIND our BTA- but I found a half decent pic of one..... If it has this general body shape, it's probably a rock anemone. They usually bury their whole foot from what I understand, and they are pretty easy to differentiate from aiptasia. PS- they're " not known for moving around the tank", but ours moved to a preferred spot within the first 24 hours.