The Rock Anemone (or Flower Anemone) is an interesting creature. It likes meaty foods, but doesn't grow much larger than 4" in diameter. The base is locked firmly in a crevice, but it changes shape quite quickly. During feedings, the mouth enlarges and resembles two lips. They come in various colors - I've seen brown/green, light green, and orange. It is quite sticky and will eat anything that ventures too closely. So, it's Reef safe-ish, buyer beware.