In a pan over medium high heat, place the tacos to get a slight crisp and to aerate them for about 30 seconds on each side. This creates a lighter finish. Set aside.
Beer Battered Fish
Slice of the fish into the sizes that you want your fish tacos to be; usually two pieces or so go in one fish tacos, so cut it a size appropriate to your tacos.
Mix the flour, salt, pepper and garlic together. Add the beer and whisk it in until there are no clumps.
Heat oil in a medium sized pan over high heat. Have a splash guard nearby if you own one. Dip the fish cutlets into the beer batter until coated. You want the batter to be quick. Quickly place into the oil ONLY when it begins to sizzle. You can test the oil by putting a piece of the onion the pico de gallo into the oil to see if it sizzles.
Fry fish for about 3 minutes on each size, or until the batter has been cooked and has browned on each side. Remove and place on a paper towel to remove excess oil.
Pico de Gallo
Mix all of the ingredients except the lime and coriander, combining until mixed together. Squeeze the limes over the mixture - you want the pico de gallo to soak in the lime juice, so ensure the entire mixture is covered slightly with the juice. Allow to soak for about 15 minutes to ensure all the flavours are extracted - This can be done before the fish is even battered. After soaked, add cilantro and mix.
Mix the sriracha and mayonnaise. I would advise adding two teaspoons of Sriracha at a time to ensure you get it to your desired spiciness.
Add a squeeze of lime in the mixture. Place in a squeeze bottle if you have own to make for easier squeezing onto the tacos.
Putting it all together
Place the fish in the taco.
Add some pico de gallo and squeeze the sriracha sauce over it all.
Serve tacos with limes for an extra citrus flavour.