Have a buddy that is breeding pure Blue Velvet Shrimp. Not sure how many people here have freshwater tanks but these guys look killer. $6ea or 5 for $25 don't miss out.
Doubt it. Neocardinia sp. are extremely small and would make very easy targets for a betta. I had a colony of dwarf shrimp in a tank with a pair of scarlet badis...same feeding habits as a betta but extremely small (~1"). At first they only fed on the shrimp fry when they had the chance...but they eventually learned how to effectively hunt the adults and decimated my colony pretty quickly.