HI there,
Well, according to my seastar insider, it is a bit tough to tell from the picture for certain. His best call is that it is a species of
Echinaster from the Atlantic. Echinaster echinophorus, which looks quite different, is nontheless a fairly common reef safe star in the hobby. It is orange, with big spikes...you may have seen it before. Echinaster is considered to have a diet and requirements similar to all other reef safe stars like Linckia. They are going to feed exclusively on the LR, be it algal/bacterial films, the critters that feed on that, or sponges, tunicates, etc which encrust the rock.
Any chance for a closer picture, perhaps a closer picture of the animal? He is looking for some close detail of the surface. If not, it is a good enough guess I think...enough to know that it should be reef safe.
Pretty guy!
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Edit: In reading through a book on Caribbean echinoderms, I think it is quite possibly it is Echinaster sentus. The color of this is described as such:
(From "Sea stars, sea urchins and allies, Echinoderms of Florida and the Caribbean" by Pawson, Hendler, Miller and Kier)
Echinaster sentus is reported to be deep red, reddish brown, dark purple, pale violet, yellow brown, or purple....The upper surface has a white ground color and contrasting orange-brown spines and violet papulae. The tube feet are orange
This is a good possibility. Papulae are little outpocketings of the body wall, generally used in respiration...and may make the surface of the animal look blurry or fuzzy when viewed from the side. It looks like you have some purplish bits on there, so this might be a good match!