I've never been a huge fan of
Frederick, although I don't mind it anymore. I've been trying to force myself to like it more because I'd potentially use it as a middle name for a future son, since it's my father's middle name and his father's first name.
If a
Frederick and his family didn't want him to be called
Fred or
Freddie, they could just tell people or correct people, and it would be alright. I've actually begun telling people my son's name is
Ben because if I tell them it's
Benjamin, they'll call him
Benjamin, and we don't call him that.
Frederico is alright.
My favorite form of
Frederick is
Friedrich.