Mix all the seasonings (paprika, dried parsley, red pepper flakes, garlic powder, onion powder, bouillion seasoning if you're using it, salt and pepper) and set aside.
Preheat your oven to 425 F. Grease a baking dish and place the fish in a single layer, or line it with parchment paper before you place the fish if you desire. Sprinkle the seasoning on both sides of the fish fillets. Top with sliced lemons, and drizzle the melted butter or oil over the fish fillets, ensuring they are well coated.
Add sliced onion, peeled garlic, and small fresh ginger to the baking pan before adding the fish or just add to the top. Squeeze one or two of the lemon slice juice into the fish. You don't have to use onion if you don't like it.
Bake the fish fillets in the preheated oven for about 12 minutes or more until the fish is cooked and flakes easily with a fork. The exact cooking time may vary depending on the thickness of the fillets, so keep an eye on them.
Once cooked, remove the fish fillets from the oven and drizzle them with fresh lemon juice if you desire. Garnish with herbs of your choice, such as chopped parsley or cilantro, if desired.
Serve with your favorite side dish and enjoy your meal.
I added garlic cloves and ginger for more flavor; you don't have to do this. Also, if you don't want to use garlic powder and onion powered, you can melt your butter, add minced garlic onto it, and coat the fish with it.