Shad is an offshore epipelagic filter-feeding fish, mainly distributed in the South China Sea and the East China Sea, mainly feeding on plankton. Every year in late spring and early summer, they migrate to the river to reproduce, after spawning the parent fish to return to the bosom of the sea, the young fish into the tributaries or lakes to grow, in order to prevent its loss in the processing and cooking, so the processing of anchovies generally do not go to the scales. This is also one of the few species that do not need to be scaled and cooked directly. But anchovies do not go to the scales have a certain timeliness, every year before the Qingming people usually do not go to the scales when processing anchovies, anchovy steaming usually do not scrape the scales of the fish, the scales of the fish is the essence of the fresh flavor. But there are also hanging scales steaming practice, one, after scraping down the fish scales, with a needle will be cotton threaded scales into a string, draped over the top of the fish with onions, ginger, wine and other condiments steaming.

Maximum can be more than half a meter, weight can be more than 5 kilograms, the back of the body is dark green or light green, the side of the body and the abdomen silvery white, the mouth milky white, juvenile period in the rivers and lakes in the survival of the fish, grow to about 15 centimeters into the sea, in the middle and upper waters of the ocean to grow. Year after year on time, so called shad. Yellowtail sex fierce, swim quickly, sharp scales, so also known as "mixed river dragon". Yellowtail and the Yellow River carp, Lake Taihu silverfish, Songjiang perch and known as China's history of the "four great fish". Herring, which belongs to the same herring family, is very similar in appearance to the shad, and has been introduced as a substitute for shad in the last decade. Herring populations are in good condition, due to differences in dietary habits.

Shad meat is very tender, delicious flavor, shad scales are very large, shiny, eat shad scales should be retained, eating shad in China also has a long history, many poets have reflected in the verse, steamed shad can ensure that the nutrition is not lost, every year at the turn of spring and summer, shad will be from the Yangtze River estuary upstream, return to freshwater to find a suitable spawning ground, spawning and then return to the sea. In this migratory time, the shad body has accumulated a wealth of nutrients, especially its skin under the scales, accumulated full of fat.