happyreefer,
these guys are very expensive (>$500). During the 80's, they were relatively common. However, since the US uprooted it's military station in the Ascension islands (in the Atlantic between the Americas and Africa), extremely few specimen have been collected. They're a hardy, shallow water Centropyge species that is similar to C.acanthops in behavior and physiology. Like all Centropyges, they are not 100% reefsafe. Beautiful fish. Just don't expect to see one in your LFS (or even mail order). And if you are fortunate enough to find one, be prepared to pay hundreds.