Yeah, black aros will lose that "penquin" look after they've reach about 10" or so??... they will get a bluish/greyish color tinge on the body w/ pinkish indigo color outline on the fins. Personally, I prefer the black aros colors over the silvers, but that's just me... All aro sp. are awesome!The blue tinge is just part of their juvenile coloration. They grow out of that around a foot or so. They still have a slightly different body color from a silver, but unless you keep them side by side (like me) it would be hard to tell.
Happy keeping and enjoy!