In a food processor or blender, add the fish or tuna. Squeeze in the lemon juice and add the garlic powder, pepper, and salt to taste.
Add 2 tablespoons of the beaten egg and 2 tablespoons of the ground bread.
Mix well until you get a uniform mixture and start shaping the patties. If the mixture feels too loose, add a bit more egg and ground bread until you reach the right consistency to form the croquettes.
Shape each croquette and coat it in breading one at a time. A favorite tip of mine: grind whole wheat bread with a little garlic salt and Italian herbs for extra-flavorful breading.
Spray your skillet with a light coat of cooking oil. Place the croquettes over medium heat and cover the pan so they cook more evenly and quickly, without needing to be deep fried.
Once golden on one side, flip each croquette. Total cooking time is 6 to 8 minutes.