Combine coconut aminos, garlic, and Sriracha. Place the barramundi filets in a bowl or ziploc bag and cover with the marinade. Refrigerate for about 20 minutes.
For the green sauce
Place all ingredients in a blender or food processor and mix well.
For the packets
Bring a pot of water with steamer basket to a boil.
Place each filet on a banana leaf and top with 1/2 tablespoon of butter or ghee, 1 sprig of cilantro, a few carrot sticks, 2 lime slices, and 2 slices of ginger.
Fold the leaf into a packet and secure with a thin strip of banana leaf.
Steam for approximately 10 minutes.
Remove the packets, open, and top with the green sauce. Enjoy!
Notes
It might be necessary to soften the banana leaves over a oven burner before wrapping the fish.