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