In a small bowl, combine cilantro or basil, paprika, salt, black pepper, cumin, thyme or oregano, garlic, lemon juice and olive oil. Mix well.
Heat tagine on the stove top. Add 1 TBSP coconut oil to melt. Layer in slices of onion and zucchini in bottom of tagine. Sprinkle 2 TBSP of spice mixture over the vegetables
If fish has skin on any of it's sides, remove it. Rub all sides of fish with some of the remaining spice mixture. Place on top of vegetables. Cover fish with tomato slices and sprinkle with remaining spice mixture. Top with lemon slices.
Cover and cook on low heat until fish is cooked through (~30 minutes). ALTERNATIVELY: Heat oven to 300 degrees and bake everything except the fish and lemon slices for 1 hour. Add the fish and lemon slices with 10-20 min to go in the cooking process.