Red Cherry Shrimp are very attractive dwarf shrimp. But often people who buy them are somewhat disappointed by the color of their new arrivals. If you didn't get the bright red shrimp you expected, consider the following:
Are your shrimp young?
Most shrimp do not get their full color until they are nearly adult. And most breeders prefer to ship juveniles to their customers. Juvenile shrimp cope much better with shipping and they adapt better to new water parameters.
Did your shrimp just arrive?
Stress with cause shrimp to lose color, just as it does with fish.
Did you see the parent stock?
Not all sellers show pictures of their shrimp, but a generic stock shot. It may be that you bought from a less vividly colored line.
Did you get a lot of males?
Remember that males are typically clear with just a few bands or speckles of red. So be sure not to cull out all your poorly colored specimens, you need to leave some males!
Are your expectations realistic?
What you will see online are peoples "show off" pictures. I have one female shrimp who is all red, but she is just one of twenty. Keep in mind that pictures you see online are not usually of "typical" specimens. The reddest shrimp are adult females with eggs, and even these will usually be 'mostly' red rather than entirely red all over--like my gals shown below hanging out on top of the filter. The yellow areas are the eggs they are holding with their swimmerettes.
But if you really want to turn up the saturation on your shrimp, there are some things you can do, see this post.