Steelhead and rainbow trout are the same species, but steelhead are anadromous, meaning that, like salmon, they migrate from the ocean to freshwater to spawn. Salmon and arctic char are a good substitute if you have trouble finding steelhead. The creamy barley the fish is served with has a texture similar to risotto, and toasting the grains before cooking gives the dish a nutty flavor. A knob of fresh horseradish is worth seeking out for this; it has a more nuanced flavor than jarred. Serve this healthy fish recipe with a glass of chenin blanc for an elegant and hearty dinner.