Fish stocks are a haphazard venture. Any lean white saltwater fish heads and bones are best: halibut, flounder, cod, etc. Oily, fatty fish such as salmon or mackerel are not recommended. If you have shrimp or any shellfish shells, add them to sweeten the broth. Besides the ingredients listed below, you can chop and cook any odds and ends of vegetables or herbs you care to use, including fennel, leeks, spinach, kale, basil. If your cioppino recipe includes leeks or a fennel bulb, toss the coarsely chopped tops and bottoms of both into the stock. With the latest batch, I tossed in broccoli, cauliflower, small tomatoes and carrots – all left over from a veggie tray.
Use 1/2 teaspoon of each or to taste, ideally bound up in a cheesecloth sachet or large tea ball
Heat salted water in large pot. Place fish heads, bones in water, bring to boil. Reduce heat and move any foam that collects on the surface.
Add all remaining ingredients including dried herbs. Simmer for 20 minutes or more.
Remove from heat, allow to cool slightly, then strain broth through a colander.
Add broth to whatever seafood dish being prepared. If you make more stock than needed, it can be kept frozen for at least a couple of months.
Note: Some recipes call for the onions, garlic and other veggies and for the fish parts to be lightly sautéed in butter and/or olive oil before adding water. Sauté the white veggies up to 5 minutes until the onions are opaque; sauté fish 2-5 minutes until bones are opaque. To save time, I did not sauté anything here and turned out a hearty fish stock; sautéing the veggies and the fish parts may add even more flavor to the final broth.