Put the warm water in a jug or bowl, add the egg white powder and lightly whisk until the egg white powder is dissolved. Set aside.
Place the pork panko, onion and garlic powders and dried parsley in a shallow dish and whisk well until completely mixed.
Cut each piece of fish into smaller, uniform pieces and then pat each piece well with kitchen paper to dry them off.
Dip each piece of fish in the egg white mixture, shake to remove excess and then lay it in the pork panko mixture* in the shallow dish. Spoon panko over the top of the fish and press gently down to help the coating stick.
Move the coated fish to a piece of parchment paper. Continue this process until all the pieces of fish are coated.
Put the avocado oil in a large skillet** over high heat, until the oil shimmers.
Put pieces of fish into the hot oil, and fry for 2-3 minutes each side until golden brown and crispy.
Remove the first batch of fish and place on a cooling rack with a sheet pan underneath to catch the oil drips.
Fry the second batch of fish and continue until all the fish is fried.