Preheat the oven to 425 degrees.
Put the sweet potatoes in a large bowl and season with salt and pepper. Add in half the avocado oil and all the spices and toss to combine. Brush the rest of the oil onto a large baking sheet and spread the potatoes out on the sheet evenly.
Bake at 425 degrees for about 25 minutes, flipping once halfway through cooking, until browned and tender.
Mix the fish spices in a small bowl to combine.
Dry the fish with paper towels and season with salt and pepper. Dredge the fish in the spice bowl to completely coat with the spices.
Bring a large nonstick frying pan to medium high heat and add the avocado oil. Add the fish to the pan and cook for about 5 minutes per side to blacken the spices and cook through.
Serve with lemon and fresh parsley.