On a baking sheet, arrange tuna, shrimp, and calamari, and season with salt and pepper. Coat a large, deep sauté pan over high heat with olive oil. Pan-sear tuna cubes 5 seconds on all sides; remove from pan to a paper-towel-lined tray. In same pan, sear shrimp and calamari for 1 minute; remove to tray with tuna. In same pan, add chorizo and stir to crumble. Remove. Add cod and bass or halibut; pan-sear. Deglaze pan with 3 cups shrimp or fish stock, and then simmer until cod and bass are tender and done, about 3 minutes. Return seared tuna, shrimp, calamari, and chorizo back into pan and simmer for 2–3 minutes. Add berbere and salt to taste.