Categories: Fish/sea, Spices/etc., Mexican 
      Yield: 6 servings 
  
      1 lb Skinned fillets of mackerel              -en escabeche 
           -or sierra                        1/4 c  Olive oil 
           Juice of 6 or 7 large limes       1/2 ts Oregano 
           -(1 1/4 to 1 1/2 cups)            1/2 ts Salt (or to taste) 
      2 md Tomatoes                                 Pepper 
      3    Or 4 canned chiles serranos     
  
  Cut fish into small cubes, about 1/2 inch, and cover them with the lime 
  juice.  Set in the bottom of the refrigerator for at least five hours, or 
  until the fish loses its transparent look and becomes opaque.  Stir from 
  time to time.