This recipe was basically stolen from A.D. Livingston and his seminal tailgate work, "Cast-Iron Cooking" (The Lyons Press, 1991).
He actually calls it Florida hash. But we adapted it with northern fish varieties and changed the name because, let's face it, New England was the nation's fishing capital for a few hundred years while Florida was still an insect-infested swamp.
In any case, it's an amazingly simple dish that is surprisingly tasty. It's also a great way to use up extra fish if you happen to have a pound or two of leftovers from dinner some night. 
We've tried to spice it up many times, but it never seems to come out quite as good as the basic recipe. Here, then, is Livingston's original recipe. It's great for warm-weather tailgates, as an accompaniment to lobsters and steamers, or other seafood dishes. It's best made in a 13-inch skillet. Serves 4 to 6.

New England fish hash

  • 2 cups white flaky fish (cod, haddock, catfish, even small striped bass filets)
  • 4 cups potatoes, diced, precooked
  • 1 cup chopped onion
  • 4 slices bacon (it never hurts to add a few more slices of bacon to anything)
  • 1 teaspoon salt (we always use kosher salt)
  • ½ teaspoon pepper (we use coarsely ground pepper)
  • ½ tablespoon vinegar
Boil or steam fresh fish until it flakes easily (leftover fish can also be used); set aside two cups. Boil four cups of diced potatoes until tender. Dice bacon slices, cook in skillet until almost done (or cook slices and crumble later -- seems like you get more fat from diced bacon, though).
Add chopped onion to bacon fat, and cook until begins to brown. Mix fish, potatoes, salt and pepper in a separate bowl. Turn this mixture into frying pan, and spread evenly. Cook mixture over medium heat until bottom starts to brown. Carefully turn over and brown the other side ("carefully" is not a word that works well in our cooking vocabulary; invariably, we end up mixing everything together haphazardly untill well done and tasty). Sprinkle with vinegar and serve.

Livingston suggests serving with a salad or lots of slice tomatoes for a lunch or light dinner, or as part of a hearty breakfast.