1. color: The body color of male diamond rainbow crucian carp is bright, usually bright red, orange or yellow, with a bright blue rainbow stripe in the middle of the body. The color of female rhombic rainbow crucian carp is relatively dark, often reddish, gray or brown.
2. Body shape: The body shape of male rhombic rainbow crucian carp is usually slender, and the dorsal fin and anal fin may be longer. The female diamond rainbow crucian carp is relatively shorter and fatter.
3. Behavior: Observing the behavior of diamond rainbow crucian carp can also help us distinguish between males and females. Male diamond rainbow crucian carp may show more intense courtship behavior during the breeding season, including chasing and fighting. The female diamond rainbow crucian carp is quieter.