Gut a small-sized aji and remove its gills. Dredge it in flour and fry in oil heated to 170 degrees Celsius for about 10 minutes. Meanwhile, mix vinegar, sugar, soy sauce, salt, water, and red chiles to make sauce.
Soak the deep-fried fish in the sauce mixture along with chopped vegetables. Once the fish soaks up the flavors, it is ready to serve. The dish is said to be based on escabeche in Spain and Portugal, which was modified by the Japanese.