He is a short light-olive green fish with dark olive green lips. He wears a lavender suit that fits his position, short black hair, and a lavender hat with a light yellow feather. He also has a yellow diamond and a "N" in the center of his suit.
He liked that Mindy thinks that Neptune is cruel and inhumane, and wished for him to be compassionate and understandable. Neptune later turned around at the end of the film.