The shrimp that are in my community tank are not specifically fed, they take what's left. They will eat almost anything but I do think that they benefit from a varied diet.
In my shrimp only tank I feed them when all of them are feeding off the moss i.e. there is no food left lying around. The community tank has 4 different types of food due to the differing types of fish but the shrimp eat everything, algae wafers being their favourite. Therefore I have a few days a week when I don't feed algae wafers which forces them to have a more varied diet.
Shrimp are easy to over feed because they feed 24/7, unlike fish which eat the food within 3-5 minutes, so there is often food lying in the tank. This can turn the tank quite quickly if food is lying around for longer than a day.
Hope that's of some help.
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