For each foil pack tear off 2, two foot sections of aluminum foil. Place them on top of each other in two different directions, like a plus sign.
Spray the foil generously with non-stick spray.
Place 1/4 of the rice in the center and spread out evenly.
Place 1/4 of the onion slices on top of the rice.
Cover the rice and onion with 1/4 of the squash slices.
Sprinkle the squash slices with the seasoning.
Lay 1/4 of the butter slices on top of the squash.
Lay 1/4 of the fish fillets over the butter, and sprinkle with seasoning.
Lay 1/4 of the lemon slices over the top.
Fold the foil up to form a packet - you want it tight to trap in all of the steam and moisture.
Place the foil packs on the grate over a fire or grill and cook for 5-6 minutes on each side.
Unfold carefully and enjoy!