Use whatever fish you have available, but a firm, white fish is best. Use fresh-rendered lard if you want to be authentic, but any vegetable oil works fine. Serve with your favorite salsas. Oh, and yes, it's good in a tortilla, too.
Season the fish with salt, pepper and garlic powder, then coat well with the beaten egg. Dust in the flour, pressing it in well. You want some eggy bits coated in flour to adhere to the fish; this give you a better texture. Put on a plate in one layer and set in the fridge for 1 hour.
Pour the oil into a large frying pan and get it very hot, about 350F to 360F. Fry your fish hard, about 3 to 4 minutes per side. You want them just past golden brown. If you can't fit all the fish in your pan, set up a rack on a baking sheet in your oven and set the oven to "warm."
Serve your fried fish with a selection of salsas or hot sauces and limes.
Notes
Note:You can skip the resting step if you need to, but it won't be as good.