Can red eared sliders eat raw shrimp?

Yes. If the fish is much larger than the turtle, it is possible the the turtle will leave it alone, but things like feeder goldfish will be eaten rather quickly. If you are looking to put fish in the tank as pets, do not, as they will most likely be eaten. If you are looking for fish to specifically feed to the turtle, ask your local pet store what fish to purchase to give them the best nutrients needed.