Prep Shrimp: Remove the shells from 12 jumbo raw shrimp. Place the shells in a cheesecloth, bring corners up and use kitchen twine to tie the pouch around the shells. Set aside. Keep the raw shrimp in an airtight container in the fridge until ready.
Sauté: In a large dutch oven add 4 tablespoons butter on medium-high heat and let melt. Add chopped onion. Stir continuously for 2-4 minutes or until onions start to cook down. Push onions to the sides of the pan and add 2 teaspoons garlic in the middle. Add 2 tablespoons extra virgin olive oil on top of garlic and let it cook until it becomes fragrant. Then mix garlic and onion together and continue to let it cook down for another minute.
Season: Add chopped celery, ⅛ teaspoon salt, and a pinch ground black pepper. Let that cook down with the garlic and onion, still stirring, for another 2-4 minutes.
Simmer Broth: Add 2 cups seafood stock, 30 ounces full fat coconut milk, 15 ounces diced fire-roasted tomatoes, 1 teaspoon paprika, 1 teaspoon salt, and a pinch red pepper flakes. Stir to combine. Place the tied cheesecloth of shrimp shells in the broth and let simmer 1 hour.
Cook Fish: While that simmers, bring a cast iron skillet to medium-high heat and cut 1 ⅓ pounds sea bass (or swordfish) into large chunks - season with a little salt and pepper. Add 1 tablespoon butter to the skillet and sear fish approx. 1 minute on all sides (no need to cook it all the way through) - complete in batches, if needed. Remove from skillet and transfer to a plate and set aside.
Combine: Remove pouch of shrimp shells from the soup pot and discard. Add potatoes, 1 tablespoon fresh cilantro, and 1 teaspoon fresh lime juice to the broth - let simmer approx. 8-10 minutes or until potatoes are firm, but soft. Add seared fish and uncooked shrimp to the large pot. Cover and let simmer 5-10 minutes or until shrimp and fish are cooked through.
Adjust: Taste and add any additional salt, pepper, or lime juice, as desired. Serve with cooked rice, fresh cilantro, and lime wedges.
Notes
Sea Bass v. Swordfish: we used swordfish in the photos simply because that is what our deli had available at the time, but sea bass is preferred here.