Question: Where did tacos de pescado ("fish tacos") orginiate?
About the article "Taco", section "Traditional tacos".

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There are many traditional varieties of tacos:
 Tacos de Asador ("spit" or "grill" tacos) may be composed of any of the following: "carne asada tacos"; tacos de tripita ("tripe tacos"), grilled until crisp; and, "chorizo asado" (traditional Spanish style sausage).
Each type is served on two overlapped small tortillas and sometimes garnished with guacamole, salsa, onions, and cilantro.
Also prepared on the grill is a sandwiched taco called "mulita" ("little mule") made with meat served between two tortillas and garnished with Oaxaca style cheese.
""Mulita"" is used to describe these types of sandwiched tacos in the Northern States of Mexico, while they are known as Gringa in the Mexican south and are prepared using wheat flour tortillas.
Tacos may also be served with salsa.
 Tacos de Cabeza or head tacos, in which there is a flat punctured metal plate from which steam emerges to cook the head of the cow.
These include: "Cabeza", a serving of the muscles of the head; "Sesos" ("brains"); "Lengua" ("tongue"); "Cachete" ("cheeks"); "Trompa" ("lips"); and, "Ojo" ("eye").
Tortillas for these tacos are warmed on the same steaming plate for a different consistency.
These tacos are typically served in pairs, and also include salsa, onion and cilantro with occasional use of guacamole.
 Tacos de Cazo for which a metal bowl filled with lard is typically used as a deep-fryer.
Meats for these types of tacos typically include: "Tripa" ("tripe", usually from a pig instead of a cow); "Suadero" (tender beef cuts), "Carnitas" and "Buche" (Literally, ""crop"", as in "bird's crop"; here, it is fried pig's esophagus.
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 Tacos sudados ("sweaty tacos") are made by filling soft tortillas with a spicy meat mixture, then placing them in a basket covered with cloth.
The covering keeps the tacos warm and traps steam ("sweat") which softens them.
 Tacos Al pastor/De Adobada ("shepherd style") are made of thin pork steaks seasoned with adobo seasoning, then skewered and overlapped on one another on a vertical rotisserie cooked and flame-broiled as it spins.
 Tacos dorados (fried tacos, literally, "golden tacos") called "flauta"s ("flute", because of the shape), or taquitos, for which the tortillas are filled with pre-cooked shredded chicken, beef or "barbacoa", rolled into an elongated cylinder and deep-fried until crisp.
They are sometimes cooked in a microwave oven or broiled.
 Tacos de pescado ("fish tacos") originated in Baja California in Mexico, where they consist of grilled or fried fish, lettuce or cabbage, pico de gallo, and a sour cream or citrus/mayonnaise sauce, all placed on top of a corn or flour tortilla.
In the United States, they were first popularized by the Rubio's fast-food chain, and remain most popular in California, Colorado, and Washington.
In California, they are often found at street vendors, and a regional variation is to serve them with cabbage and coleslaw dressing on top.
 Tacos de camarones ("shrimp tacos") also originated in Baja California in Mexico.
Grilled or fried shrimp are used, usually with the same accompaniments as fish tacos: lettuce or cabbage, pico de gallo, avocado and a sour cream or citrus/mayonnaise sauce, all placed on top of a corn or flour tortilla.
As an accompaniment to tacos, many taco stands will serve whole or sliced red radishes, lime slices, salt, pickled or grilled chilis (hot peppers), and occasionally cucumber slices, or grilled cambray onions.
They serve Wahoo fish in their tacos, as well as Mahi-mahi.  
Typical foods of the municipality are: La Morisqueta, iguana soup, fish soup (bagre, carpa), corn tamales with cream (uchepos), corundas de maíz with cheese and cream, tacos de res y chivo tipo barbacoa, enchiladas con pollo y cecina. 
The specialty tacos come in different varieties to include the very popular barbacoa, fish, shrimp, beef fajitas and chicken adobado. 
In Spanish- and Portuguese-speaking countries, the close cognate "tripas" tends to denote small intestines rather than stomach lining.
Dishes of this sort include: "Tacos de tripa" — Mexican tacos filled with soft or crunchy fried small intestines