I believe that's a blue hamlet in the pic (Hypoplectrus gemma) but as I found, there's an argument out there that all hamlets are the same species, just their slight coloration differences.
IMO, there are two, the shorter, stubbier snout ones, like the Blue and Golden hamlets, and the ones with the longer, more pointed snout, like the Indigo and Black hamlets.
I suspect behavoir is identical between all of them though, should be an interesting fish. One LFS here had a huge Butter, maybe 4.5" and he was pretty cool, eat anything.