I just got a ferret and gave it a bit of special k.. will it die? didn't know it was bad?

My friend just gave me a ferret and i didnt know that grains and fruits werent good for them.. I know that now, but he was so curious i gave him two little pieces.. how bad is that? will it die or is he gonna be ok? Shoudl i take him to the vet? it was only a little.. thanks for the help! andyes i will research ferrets more before igivng him any mor etreats or anything like that