Scaleless carp, also known as mirror carp, is a variety of German carp. Its skin is shiny, smooth as a mirror, and its luster is obvious, so it is called mirror carp. There are several large scales on the lateral line, back and abdomen. Also known as Sanhua Carp, De Carp and San Li.

Mirror carp has a stout body, flat side, raised back and head, small head, big eyes and large scales on the body surface, which are arranged along the edge. There are 1 rows of complete scales from the front end of dorsal fin to the head, 1 rows of symmetrical continuous complete scales on both sides of dorsal fin, scales at the base of each fin, and a few scales on individual lateral lines. Most lateral lines are straight without branches, and some lateral lines have short branches at the end. Body color varies with different habitats, usually brown on the back and light yellow on the sides and abdomen.

Mirror carp, with few scales, fast growth, high meat content and good meat quality, was approved as an excellent aquaculture variety suitable for popularization in China by China Aquatic Variety Approval Committee. Under reasonable stocking density and better feeding conditions, mirror carp grows very fast. In Heilongjiang province, one fish with the size of 150g can be cultured in that year, and the size of commercial fish can reach more than 1kg in the next year. The survival rate of feeding is about 98%, and the overwintering maturity rate is 96%.