Baffling Disney Question!!!!?

What is GOOFY i know he is supposed to be a DOG but what if he isn't!!! Pluto is a DOG!! here is the weird part Mickey is with Minnie (Both Mice) Donald with Daisy (ducks)But Goofy is with Henrietta Hippo? (DOG HIPPO?) I think Ol' Walt Thought a Skinny Hippo would look silly or GOOFY!!! Anyways I have always wondered