1. For Blue-cheese Sauce, line a sieve with paper towel or coffee filter; set over a bowl. Spoon yogurt into sieve; cover and refrigerate 1 hour to drain. Combine drained yogurt, blue cheese, mayonnaise, garlic, and cucumber in medium bowl. Cover and refrigerate 15 minutes.
2. Meanwhile, combine cornmeal, ground red pepper, and salt in 9-inch pie plate. Dip each fillet in egg, then coat in cornmeal, shaking off excess.
3. Heat oil and 1 tablespoon butter in large nonstick skillet over medium-high heat. Fry fish 3 to 4 minutes per side, until golden brown and cooked through. Transfer fish to each of four serving plates. Melt remaining 1 tablespoon butter in same skillet over low heat; remove from heat. Stir in pepper sauce; divide and drizzle over fish, scraping pan with a rubber spatula. Serve immediately. Makes 4 servings.