Dave[/quote] Actually, I've the same thinking. Nevertheless, a friend advised that for Royal, using the dark substrate & background with limited lights will darken its color. So the Royal will be dark and not so attractive.
By using lighter substrate, white background & using daylight will enchance and brighten the Royal color and its marking...
So, which is which ?

[/quote]
To clarify, I said that the color deepens, not darkens, and I use bright , full spectrum lights on my freshwater tanks (roughly 4 or 5 watts per US gallon) for the plant's benefit; I provide overhangs of bogwood and plants to filter that light, as in IMO, fish look better swimming though dappled 'sunlight'.
According to everything I've read and observed, fish adapt to their surroundings in an attempt to 'blend in'. Thus, they pale in a tank with light substrate and surroundings, and their color deepens over a dark substrate and a midground of bogwood (which a Royal needs).
Final choice is, of course, up to you, as I'm speaking from my experience; 30+ years in the hobby. To me, fish look better and appear more 'relaxed' over a dark substrate. Not to contradict your friend, but this works for me and my fish. Enjoy your Royal; they are fascinating fish, and start planning that larger tank - a 16-18 inch Royal is a lot of fish

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Dave[/i]
I dream of L-Numbers . . .