Combine mango, red onion, jalapeno, lime juice, cilantro, and salt in a mixing bowl.
Mix gently and refrigerate while preparing the remaining ingredients.
Pat the fish dry.
Season with salt, black pepper, garlic powder, and paprika.
In a large bowl, whisk together flour, cornstarch, baking powder, garlic powder, onion powder, salt, and paprika.
Slowly whisk in the cold beer until smooth.
Heat oil to 375 degrees.
Dip the fish into the batter and allow excess batter to drip off.
Fry for 3 to 5 minutes until golden brown, crispy, and fully cooked.
Transfer to a wire rack to drain.
Warm the corn tortillas until soft and flexible.
Keep covered until ready to assemble.
Add shredded cabbage to each tortilla.
Top with crispy fish and mango salsa.
Add cilantro crema if desired.
Finish with a squeeze of fresh lime.
Serve immediately.