To prepare the Lemon Garlic Butter Baste, in a sauté pan over medium heat, add the oil and butter and stir until butter melts. Add the garlic and lemon juice, bring to the boil and then turn off heat and set aside.
Next prepare the Conch Salad. Into a bowl combine conch, lime or lemon juice, olive oil, green onion, red onion, tomato and green pepper, chili peppers, lemon juice, barbecue seasoning and salt to taste. Set aside and marinate for about 15 minutes.
Preheat grill to high (about 550 to 600°F).
Season the Mahi Mahi steaks with lemon pepper, pressing the seasoning into the meat to adhere. Rub the seasoned steaks with oil and place, flesh side down, on to the grill. Grill, with the lid open, for about 4 to 6 minutes per side, basting liberally with Lemon Garlic Butter Baste until butter is browned and nutty in flavor and the fish is cooked through and easily flakes with a fork. Be careful not to overcook your Mahi Mahi; it is a fish best served rare.
To serve, place the grilled Mahi Mahi steaks in the center of a large plate. Spoon over Conch Salad and drizzle extra marinade over salad. Serve garnished with a wedge of lemon and a chili pepper.