Frank Fieldmouse is a male anthropomorphic mouse.
Behind the scenes
The existence of Mr Fieldmouse was implied in the 1932 story Mickey's Nephews, which introduced his wife and sons. In the 1990's, when Egmont redesigned Amelia and intended to maker her into a semi-recurring character, they established that her husband's name was Frank Fieldmouse. However, that name was never used so far in an actual comic.