Evenly coat the bottom of a sheet pan with olive oil to prevent the fish from sticking.
Mix the salt, pepper, paprika, onion and granulated garlic together.
Sprinkle the mixed dry ingredients over both sides of the filets.
Place the filets onto the sheet pan uniformly with a little space between each piece.
Place the sheet pan onto your preheated grill.
Let cook for 10-12 minutes.
Check for doneness by sticking a fork through the center of the thickest filet. If the fork slides through easily it should be done, but probe the center for temperature. Safe temperature for eating fish is 145°F.
While the fish is cooking, you can start your lime sauce.
In a small saucepan on medium-low heat, add the two sticks of butter and let them start to melt.
Mince or crush your garlic and add to the pan and let cook for 2-3 minutes.
Add in the salt and sugar and let cook another 1-2 minutes.
Add in the lime juice, turn the stove up to medium-high heat, and bring the sauce to a quick simmer.
Turn the heat off and then add in the chopped cilantro.
Warm your tortillas by either steaming in the microwave for 1 minute, wrapped in a damp paper towel, or toasting them on the grill for 1 minute per side.
Start making your tacos when the fish, sauce, and tortillas are all done. Fish first, then a little sauce on top.
Then add the condiments of your choice on top of the fish and sauce and you are ready to eat!