1. Appearance difference: sea crucian carp has a small size, wide body, body shape presenting oval shape, large fish scales, which are not easy to fall off. While freshwater crucian carp has a large body size, narrow body, body shape presents long oval, fish scales are small and easy to fall off.

2, living environment: sea crucian carp mainly live in the ocean, inhabiting the sea near the mouth of the sea. The freshwater crucian carp, on the other hand, mainly lives in rivers, lakes and other fresh waters, inhabiting the clear and sweet water.