Those are Neocaridina heteropoda var. red (aka Red Cherry Shrimp). The original Neocaridina heteropoda (as found in the wild) are normally tan, sometimes green, sometimes yellow, sometimes red. Those that breed them in Asia in captivity selectively bred for the red color and now we have the Red Cherry Shrimp. Just as the betta, a far cry from what is seen in the wild. Something so brightly red would not survive long-term in the wild with no way to hide from those that would eat them.
Cherry shrimp make a good clean-up crew but if your fish do not keep the shrimplet population under control, they can easily overtake a tank. I put 8 in their own tank and left them alone to see how they'd do. After 4 months, I traded them to my LFS. It was over 75!