In my growing-up world, paprika was used only to add a hint of color. Elsewhere, people with roots in Eastern Europe were enjoying paprika for its robust, spicy taste (not to mention color). For color but with little spicy heat, use
sweet paprika. 'Kick it up a notch' with
hot paprika to taste.
Stock. You'll get fine results with fish stock, chicken stock, or a mix of the two. You can substitute bottled clam juice for fish stock. Personal favorite: shrimp stock.
Potatoes. Any potatoes will do, but russets or Yukon Gold give a nice 'creaminess'. If the potatoes are new and have tender skins, simply wash and brush rather than peeling. You may want to lightly mash some of the potato pieces in the pot just before adding the fish.
Fish. Use firm white fish such as cod (salmon is good too). If frozen, remove fish from package and thaw in a bowl of cold water. Remove any bones and skin. Cut fish into chunks if you prefer, but it's easier to put whole fillets into the stew. When cooked, the fillet will flake apart on its own.