Get grill ready for in direct heat, at just slightly over a low flame.
If you have 4 filets then you'll need 4 squared pieces of aluminum foil, so on and so forth.
Squeeze the desired amount of Sriracha sauce into the middle of the foil, then sprinkle on a little garlic salt.
Place 1 filet on top of the sauce, adding more sauce to top of fish.
Fold up aluminum foil into little packets, ready for the grill.
Grill on low heat for about 5 minutes on one side, flip, then grill another 4-5 minutes.