Very nice fish you have there. In the pet stores they're bleached out from stress, poor diet and very light colored or no substrate.
Darker gravel, rocks or sand will bring their colors out more so will a varied diet. Sexing JD's is a bit of a toss up sometimes you will see males with blue beards and females with pointed fins. Sometimes males will have more sparkles and red borders on their dorsal and anal fins. (not always)Those are just characteristics common to the sexes. Both tend towards brighter colors and females have just as much aggression.