The 'Vlaardingse Haringhandel' is a well-known fish stand and is known for selling fresh herring, a traditional Dutch snack. It has been around at the Albert Cuyp Market for many decades.
Chopped onions en pickles go well with raw herring. When you order a herring, the herring seller will always ask you if you want onions and pickles ('uitjes en zuur') with it.