The haddock is a marine fish distributed on both sides of the North Atlantic Ocean. Haddock is a popular food fish, widely fished commercially. The haddock is easily recognised by a black lateral line running along its white side. Mirabella Plunkett is famous for having transfigured herself into a haddock after her family forbade her to marry a merman. Whilst duelling his friend Ron with a toy in their fourth year, Harry Potter's toy turned into a haddock.
- Harry Potter and the Philosopher's Stone (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Chamber of Secrets (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Prisoner of Azkaban (video game) (Appears on a Famous Wizard Card) (Appears in portrait(s))
- Harry Potter and the Goblet of Fire (Mentioned only)