Preheat oven to 375 degrees F (190C) and set out a 9x13 (or similarly sized) baking dish.
Add fish to a shallow dish or plate, drizzle with oil, and sprinkle with salt, pepper, herbs, and lime juice. Toss to coat and set in the fridge to marinate.
Heat a large pot or dutch oven over medium-high heat. Once hot, add oil, onion, tomatoes, garlic, and bell peppers. Season with salt and pepper and stir to coat.
Sauté, stirring frequently, for 8-10 minutes, occasionally covering to allow the peppers to soften. Stop when the peppers are tender but not yet mushy. Set aside.
Heat a large skillet (cast iron is best) over medium-high heat. Once hot, add fish. Cook for 2 minutes, then carefully flip and cook for 2 minutes more. You aren’t looking for the fish to be completely done — just seared on the outside.
Transfer fish to your 9x13 (or similarly sized) baking dish. Top with sautéed peppers, tomatoes, and onion and spread the veggies to achieve an even layer.
Cover with foil and bake for 10 minutes, then remove foil and bake for 3-5 minutes more to allow the top to get slightly browned.
Store leftovers in the refrigerator up to 2-3 days. Or add to freezer-safe tupperware and freeze up to 1 month (though best when fresh). Reheat in the oven or microwave until warm.
*Recipe adapted from one we learned at a cooking class in Cabo San Lucas, Mexico. *Nutrition information is a rough estimate calculated with Pacific cod fillets, avocado oil, and without optional ingredients.