It is probably Echinaster echinophorus. I believe I have mentioned this before here, so a search might turn up someone who keeps it. If it is, it is probably reef safe, but no guarantees. However, it is commonly found on mangrove roots, and not necessarily coral reefs...this would indicate that it is a film type feeder, though perhaps sponges also. It is probably not, just as with Linckia, an "algae" eater in the sense that people think.
A good question to ask is if it is from Florida/Caribbean or Pacific. If Caribbean, than it is most likely Echinaster.
If reef safe it needs a lot of LR, no other star competitors, a large mature reef tank with pristine water parameters, and a long acclimation. It may not respond to any prepared foods, as few reef safe stars do.
