Rinse/clean the fish bones and put in stockpot with all the ingredients. Bring to a boil and then simmer slowly for 30-40 minutes.
Strain the stock and then pour into a smaller pot. Heat this pot on low heat to maintain hot temperature.
Make the Puree
Boil water in the microwave in a large bowl for 2-3 minutes. Add chiles to the water and place a small saucer on top of the chiles to keep them submerged under the water. Let sit for 15-20 minutes until chiles are fully softened.
Drain the chiles and transfer to a blender. Add the garlic and water and puree to make a sauce.
Pour the puree into the stock and simmer for about 15 minutes. I completed this step the night before, seasoned further and then refrigerated to let the flavors come together further. However you can go right to the next step, just make sure you continue simmering so the stock is hot when the stew is ready.
Make the Stew
Transfer about 3 cups of the stock to a large pot and bring to a boil. Add the seasonings and mussels and cook until they open - about 4-5 minutes. Get rid of any mussels that fail to open.Remove the mussels and place in large serving bowl.
Cook the shrimp in the stock for 2 minutes. continue cooking but add the scallops for an additional two minutes. Remove all ingredients from the pot and add to the seafood bowl.
Serve seafood in individual bowls topping with the hot stock, onions, cilantro, and lime wedges.
Feel free to use your own recipe for fish stock or a store bought one, especially if you want to reduce time.Calamari, lobster, and clams are also perfectly suitable for this recipe.