Yes. You should cut back on the amount of minnows you are giving him. You should start giving your RES pellets every other day and the amount of pellets you should give him is how much you think can fit in his head. And you should also cut back on the amount of shrimp you are giving him. You should be giving it to him about every 2 weeks.
Also, every other day that you dont give your turtles pellets your should be offering him greens like lettuce, carrots, and it says what you should give your turtle in the feeding section on the forum. There is a list for things that you should and should feed your RES. But always keep offering your turtle the greens because in a while he will start to eat them.
And about the minnows that you have in your tank, I always had some but they were always to fast for my turtles to catch so i never really had a problem with it. Give your turtle minnows like every month or so for a treat. But is sounds like you are giving your RES a wonderful life! What is its name?
