A serrano pepper and a mixture of spices add zest and flavor in these appetizer servings to Salmon-and-Shrimp Ceviche.
Combine first 3 ingredients in a nonaluminum bowl. Cover and refrigerate 2 1/2 hours or until fish is opaque. Drain liquid, reserving 2 tablespoons.
Stir together salmon mixture, shrimp, and next 9 ingredients. Fold in avocado and reserved marinating liquid.