1. From the appearance, the engineering crucian carp has a thick lip, a prominent bulge on the back, a relatively small fish head and a relatively large body. The native crucian carp, on the other hand, has a slender body, a wide head and a wide tail, and looks thinner as a whole because it needs to find food and escape from natural enemies.

2. In terms of color, the engineering crucian carp is usually silver, or its belly is white and its back is gray. The color of local crucian carp is golden yellow, and its back is bluish gray.