[tamsin]

How about sundadanio axelrodi - they can be a little tricker to find depending where you are, but they have similar blue/green to the cardinals - well even nicer in my opinion. Once they colour up, they look amazing when they catch the light. Also very shrimp safe, won't guarantee they never eat a tiny baby but certainly don't seem to actively hunt them and my shrimp populations growing well. Green neons are another option - not as common as the regular kind, but nice small fish that shoal well.