Line whatever pan you are using for the fish with parchment paper
Cut the fish into the desired size
In a medium mixing bowl, mix together the dry ingredients: almond flour, coconut flour, tapioca flour, arrowroot starch, garlic powder, onion powder, and salt.
In a large bowl, mix together the eggs, olive oil, and seltzer water.
Gently mix in the dry ingredients in to the wet ingredients. A thick batter should form.
Lightly salt the fish, then dip it in the batter. The batter should be thick, and you might need to add the batter to one side of the fish, place it face down on the parchment paper, and spoon more on top. Be sure to move some batter to the sides to connect both sides of the breading.
Put the fish in the Air Fryer, and cook at 370° F for 20 minutes. After 20 minutes, flip the fish to cook on the other side.
Cook for another 15-20 minutes, until breading is completely cooked.