Preheat oven to 350°. Melt butter in a dutch oven or cast iron skillet, on medium heat. Add 1/2 cup sliced onions and 1 tsp. garlic.
Sauté 4 minutes or until tender. Stir in broth, orzo, sun dried tomatoes, salt, and pepper.
Bring to a simmer, and cook, uncovered for 15 minutes or until orzo is just tender and some liquid remains in skillet.
Stir occasionally. Remove from heat and sprinkle fish with salt and pepper.
Place fish on top of orzo, in a single layer, and cover skillet. Bake at 350° for 10 to 25 minutes or until fish flakes easily with a fork.