How to Make Seafood Stock at Home | Eater
"Michael Schlow, the chef behind a new seafood-focused Boston restaurant, says homemade seafood stock is easy and noticeably superior to store-bought. For finfish stocks he recommends using neutral white-fleshed fish (heads, tails and bones from halibut, cod, haddock, pollock, etc.) and avoiding oily fish like salmon or mackerel; keep seasoning light (thyme or parsley, with fennel and a splash of vermouth if desired) and simmer gently for about one to two hours to avoid bitterness. For shellfish stocks, chop and sauté shells in butter first to extract more flavor, consider adding a peeled orange for brightness, and a touch of tomato paste to deepen the appealing pink-red color for bisques." - Tanya Edwards
