Seviche

1 pound fillet of fish,  a firm mild fish like turbot or orange roughy
Lemon juice to cover fish
1/2 medium onion, medium dice
2 large ripe tomatoes, peeled and diced
3 T. chopped cilantro ,use parsley if you cannot locate fresh cilantro
3 T. olive oil
2 canned green chiles, finely diced
1/4 t. dried oregano
Salt and pepper to taste
2 ripe avocados, diced

Cut the fish into small cubes and place in a glass bowl. Cover with
the lemon juice (you can also use a mixture of lime and lemon juices).
Let stand in the refrigerator, covered, for at least 8 hours. This
"cooks" the fish. Now add the remaining ingredients, except avocado.
Refrigerate a few hours more. When ready to serve, stir in the
avocado.