Preheat the oven to 375 degrees F.
Place the oil in a skillet set over medium heat. Add the onion and garlic and cook 3 to 4 minutes. Add the kidney beans, tomatoes and stock. Bring to a simmer and then pour into a 9" x 13" inch baking dish. Nestle the fish into the beans. Drizzle with the lemon juice; season with salt and pepper. Cover and bake 18 minutes, or until the fish is cooked through.
Divide the fish and beans among 4 shallow bowls, sprinkle with basil and serve.
Recipe Options: Feel free to try another fish fillet in this recipe instead, such as snapper or halibut. Instead of white kidney beans, use canned chickpeas. As an alternative to just fresh basil, use a mix of chopped fresh herbs in this dish, such as basil, oregano and parsley.