Orange Roughy fish with Salsa

1/2 to 2 pounds orange roughy
2 Tbsp. fresh lemon juice
salt and pepper to tast
1/2 yellow onion, sliced
1 cup fresh or prepared salsa

Preheat oven to 400 degrees.  In a lightly oiled or sprayed glass baking dish, place fish dark side down.  Sprinkle with lemon juice, salt, and pepper.  Pace onion slices on top of fish.  Spoon salsa evenly over onion slices.  Bake until fish flakes when tested with a fork, about 20 to 25 minutes.  Serve immediately.