Very nice pair. Any idea how old they are? The male is still quite small, near the size of the female. I imagine they're not breeding as of yet? I like how they look with the black sand. I have a pair of Apisto. Cacatuoides and opted for pfs with oak leaf litter. I like it, but, I prefer the cleaner look of your black substrate. My tank bottom is just a mess, although the fish and fry do enjoy swimming thru it.
Nice pics btw!