In a large saucepan, over a medium heat, melt the butter and quickly add the onion. Cook til transparent.
Add all of the fish to the pot (the fish can be cooked or raw)along with the water. Bring to a gentle boil and turn the heat down low, simmering covered, for about 15 - 20 minutes, adding more water if necessary. this will give you a rich fish stock.
Measure out 2 cups of the fish stock, setting aside any remaining for future use. If you don't have quite enough stock, add water to the 2 cup mark and return it to the pot with the fish etc.
Add the Half & Half, stirring it in gently so you don't break up the fish to much. Sprinkle with the salt and pepper. Allow this mix to simmer another 15-20 minutes.
At the end of your cooking time, stir in the saffron, more may be added for a richer flavor.
NOTE: If you desire a thicker chowder, mix a flour and water paste and add to desired consistency. For a thinner chowder, add your leftover fish stock or water.
Serve hot along with chunks of crusty bread and plenty of butter!