I feed my fish color enhancing flakes for breakfast everyday, and for dinner rotate between frozen
brine shrimp and frozen bloodworms. I don't know of anything else that would help color them up (other than maybe live food).
The color enhancing lights are supposed to be of a wavelength that enhances the colors fish generally are, so while I haven't any experiance with them, I would think they would help.
Your fish will probably color up as the age also. Additionally, male fish when in the company of female fish of the same species seem to color up.