In a mixing bowl, combine the drained tuna, breadcrumbs, mayonnaise, eggs, chopped onion, parsley, garlic powder, salt, and pepper. Mix well with a fork until all ingredients are thoroughly combined.
Shape the mixture into patties, about 3 inches in diameter and 1 inch thick. You should have about 8 patties.
Heat the olive oil in a frying pan over medium heat. Once hot, carefully add the patties to the skillet, making sure not to overcrowd the pan. You may need to fry them in batches.
Cook for about 4-5 minutes on each side, or until they are golden brown and crispy.
Once cooked, transfer the patties to a plate lined with paper towels to drain any excess oil.
Serve warm, with your choice of sides or on a bun.