To make the batter: in a bowl, stir together the flour, garlic salt, and ground chile. Pour in the beer, whisking to make a smooth batter. Cover and let stand for up to 1 hour.
Meanwhile, make the creamy salsa: In a small bowl, stir together the mayonnaise, yogurt, and ketchup until blended. Set aside.
To make the tacos: Remove the skin from the fillets and run your fingers over the fillet to check for and remove any embedded bones, using tweezers if necessary. Cut the fish into 8 strips, each 3 - 4 inches (7.5 - 10 cm) long and 3/4 inch (2cm) and place in a nonaluminum bowl. Sprinkle wiht the lime juice, garlic salt, and ground chile and toss to mix. Let marinate at room temperature for 10 minutes. Pour the oil to a depth of 1 inch (2.5 cm) into a deep-frying pan and heat to 375F (190c) on a deep-frying thermometer. This may take up to 5 minutes.
Meanwhile, heat a comal, griddle, or heavy frying pan over medium heat. When it is hot, stack 2 or 3 tortillas on the heated surface and leave for a few seconds. Flip the tortillas,rotating them every second or so until all are hot. Wrap in a dry kitchen towel and repeat with the remaining tortillas. They should keep warm for 10 minutes. If they are to be held longer, wrap a damp towel around the dry towel and place the packet in a 200f (95c) oven.
Pat the fish strips dry with paper towels. One at a time, dip a strip into the batter, allowing the excess to drip off, and slip into the hot oil. Do not allow the pieces to touch. Fry until the strips are crisp and golden, about 7 minutes. Using a slotted spatula, transfer to paper towels to drain, When all are fried, transfer to a warm serving plate. Put the salsa fresca, cabbage, and limes in separate small bowls and set on the table along with the fish, creamy salsa, tortillas,avocado, and hot-pepper sauce. Let the diners make their own tacos, wrapping the fish in a tortilla and adding the other items.