What to do with a loose mushroom

So I have this new mushroom coral. It's a nice blue/green with some red stripes, though it's very small and came completely loose.



Right now I have it rubber banded to a rock, but the rubber band almost covers the whole mushroom. I know they're hardy, but it just seems a bit abusive.



I know they're a bit like an anemone and can move around. Is this even a battle worth fighting, or should I just let it fly free and find its own place to settle?