It was supposed to be...but I don't know how long it's been in the LFS's "curing" tanks. There certainly is "life" on and in the rocks but the diversity is not as much as I hoped. I can see a few sponges that are definitely growing, a few limpets, somethings that look like small barnacles, pods, a number of tube worms, something that's hard red and knobbly (but is only 1/4 inch in diameter and 1/8th high but is growing - slowly), and a few really tiny crabs that I can see chowing down on what looks like some decaying matter. As for coralline - there is some purple, some light green (like the Tomally of a Lobster), a few spots of yellow (of all things), and various shades of brown. Can coralline be an off-white color? I can see layers of white calcification that's on top of some of the rocks (that's not the actual rocks itself).