I recently added San colour tiles to the bottom of my bare bottom tank. Though the fish is more active in the tank now I feel that the colour is bleached out. Would you remove the tiles? Here are the before and after taken two weeks apart.
I like the look of the tank with the tiles (not a big bare bottom fan), but the flowerhorn definitely looks better in the first pic. You can try a darker tile like
..puSkar.. suggested.
Cichlids will change colors to match their environment, so it stands to reason a dark fish will look best against dark backgrounds.
True, too dark will alter colors just as much.
I think a grey or blue would be best for your fh (though, this is all a matter of opinion, whatever makes you happiest is the color you should go for).