Mix tapioca flour, almond flour, garlic powder, sea salt, and old bay together in a wide mouth bowl.
Whisk egg and coconut milk together in another wide mouth bowl.
Heat avocado oil in a large skillet over medium heat.
Dredge fillets in the egg mixture and then in the flour mixture. Place the fillets on wax paper.
When the oil is hot, add the fish fillets to the pan. You can test the oil by tossing a small bit of the extra breading in the pan. If it sizzles and starts to brown then the oil is hot enough.
Fry the fillets for 2-3 minutes per side, depending on thickness. For 1/4" fillets it will be around 2 minutes and for 1/2" fillets around 3 minutes. Flip the fillets with a large, thin spatula.
Remove the fillets to a cooling rack. I like to use a baking sheet covered with paper towels and place the cooling rack on top.