Imo the lighter one has the most potential but man to be completely honest with you your not going to be able to tell unless they are in a segregated tank for a little while if their raised with other fish theres two factors that will mess with their development and thats competition for food either they get too much or too little and dominants the dominant male will always display more color and a bigger kok flowerline pearls ect. it might not be what you want to do but if you take a ten gallon silicone a divider in and leave them in there for 3 or 4 weeks with a small mirror on each side their shape and color will greatly improve it will keep you from robbing youself and when your done with the tank youll have a quarantine tank its a win win
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