"This recipe is awesome! So delicious! Grinding the fish is key! It absorbs all the flavors and the lime juice cooks the fish! People will ask you for the recipe! My bf asks for it at least very other week and my family expects it at every gathering! I usually cook it overnight! The flavor is amazing! Serve with chips or tostadas, sliced avocados, and for those spice seekers a whole serrano. Hope you guys enjoy!"
Process swai fish in a food processor until pureed and mushy; transfer to lime juice, stirring until all fish is covered in juice. Add tomatoes to fish mixture.
Blend red onion, cilantro, and serrano chile peppers in a blender until desired consistency is reached; spoon into fish mixture. Season mixture with salt and black pepper. Cover bowl with aluminum foil.
Refrigerate until fish is tender and "cooked", at least 2 hours.