In a bowl, combine the flour, garlic powder, onion powder, smoked pap, salt and chili powder and whisk to combine. Pour in the beer and whisk until a smooth batter forms.
Heat a large nonstick skillet over medium-high heat and add the oil. Dip the fish in the batter and coat it completely, then drop it in the skillet to fry. Let each piece of fish fry until the sides appear golden and crispy, about 3 to 4 minutes per side. Gently remove the pieces with a spatula and place them on a paper towel to absorb any liquid. Repeat with all the fish, adding more oil if needed.
In a small bowl, stir together the cabbage with the lime juice and a pinch of salt and pepper.
To assemble the tacos, warm the flour tortillas. Add a few pieces of the fish on top, followed by the cabbage, the salsa and then a drizzle of the crema. Serve!