Preheat oven to 350 degrees Fahrenheit.
On a large plate, add tilapia and cover with lemon zest, juice from lemons, half of olive oil, minced garlic and salt and pepper. Let marinate for 30+ minutes in the fridge.
Meanwhile, wash and slice potatoes. Add on a baking dish, drizzle with olive oil and bake for 30 minutes.
Remove from oven and add tilapia on top of potatoes. Add some fresh lemon slices and fresh parsley. Bake for an additional 20 minutes. Enjoy!