Place fish fillets into a large ziploc bag and pour juice from two lemons over fish. Marinate in the fridge for 30 minutes.
Place fish on grill over aluminum foil that has been sprayed with cooking spray. Sprinkle with salt and pepper. Cook over medium low heat for 4-5 minutes on both sides.
Guacamole
Mash avocados in a medium bowl.
Add tomatoes, onions, peppers, garlic, and cilantro to the mashed avocado. Squeeze lime over top.
Mix together and add salt and pepper to taste.
Tacos
Lay two tortillas down one on top of each other. Layer coleslaw mix, guacamole, and fish on top of tortillas. Garnish with cilantro.