In a medium bowl, whisk together the flour, baking powder, and salt.
Slowly whisk in the chilled beer until the batter is smooth and contains no lumps.
In a small bowl, mix the mayonnaise, sour cream, lime juice, and hot sauce to create the Baja crema.
Heat 2 inches of vegetable oil in a heavy-bottomed pot or deep skillet to 375°F (190°C).
Pat the fish strips completely dry with paper towels to ensure the batter adheres.
Dip fish strips into the batter, letting excess drip off, and carefully place in the hot oil.
Fry the fish in batches for 3 to 4 minutes until the coating is golden brown and crispy.
Drain the fried fish on a wire rack or paper towels.
Warm the corn tortillas on a dry griddle or over an open flame until pliable.
Assemble tacos by placing one piece of fish on each tortilla, followed by shredded cabbage, cilantro, and a drizzle of the prepared crema.