Preheat oven to 375 degrees F (190 degrees C).

In a food processor or blender, pulse together macadamia nuts and breadcrumbs until finely ground. Pour nut mixture onto a plate, and coat fish fillets on both sides.

Heat butter in a large skillet over medium heat. Fry fillets on both sides until nuts are golden brown. Remove to a baking pan.

Add shallots to skillet, and cook until translucent. Stir in chicken stock. Mix in pineapple, papaya, mango, coconut, and habanero peppers. Season with salt, pepper, and sugar to taste. Simmer until sauce is thick, about 30 minutes. Strain to remove peppers, fruit, and shallots. Reserve sauce in a pan over low heat.

Bake mahi mahi in preheated oven about 10 minutes, until internal temperature reaches 140 degrees F. Remove fish, and lightly coat with sauce.