If the anemone was eating a meaty diet regularly, was not bleached, was attached properly for it's species, then it really just needs:
clean water, mild random flow, smaller foods, and to be protected from predators/irritants(abusive clowns, shrimp, cowries, butterflies, kalk drip, reactor drip, etc.)
If it never attached, just bounced around in the current, never ate, was bleaching, or even worse, showing signs of erosion on the column; then challenges lie ahead for anyone.
Post a picture, a number of folks can help you out, provide guidance, and possibly point you to a local reefer that can take it if that is your decision.