Slice your pineapple bark off according to the size of your fish. Season the fish with salt and pepper. Place the pineapple bark onto the grill and place your fish on top. Pour some of the soy sauce and brown sugar mixture onto the fish.
Place another piece of bark on top of the fish and turn your grill to high heat. Place slices of pineapple on the other side of the grill.
Flip your pineapple slices over once they have nice marks on them.
Remove the pineapple slices from the heat. Open up the bark to check the cooking. If the fish still looks raw on one side, close the bark and flip.
Once fish is finished remove from the heat.
Pour some more of the soy sauce and brown sugar mixture onto the fish, serve and enjoy!