Preheat the oven to 350 degrees F (175 degrees C).
Place butter in a microwave-safe bowl and melt in the microwave, about 30 seconds. Add crushed garlic to butter and stir. Season sauce with salt, pepper, and oregano.
Place salmon fillets on a large sheet of aluminum foil and pour sauce on top. Wrap tightly to enclose; place on a baking sheet.
Bake in the preheated oven until fish flakes easily with a fork, about 20 minutes.
