Combine the shallots, garlic, oregano, sugar, olive oil, balsamic, lime juice, tequila, salt, and pepper in a gallon-sized seal-able bag; shake to combine.
Add the tilapia to the mixture and store in the refrigerator 2 to 4 hours, turning every 30 minutes.
Preheat oven to 450 degrees F (230 degrees C).
Line a baking sheet with parchment paper
Arrange the fish on the prepared baking sheet.
Discard remaining marinade.
Bake in the preheated oven until the fish flakes easily with a fork, about 10 minutes.