Different fish divide male and female in different ways, but one thing is the same, that is, the abdomen of mature female fish will swell. In addition, for most fish, females are larger than males, and during the reproductive season, males tend to have multiple colors or beads on the fish body or pectoral fins. Distinguishing male and female fish is mainly for pairing when breeding, controlling the ratio of male and female, and making it easier to pair successfully.

1. Guppies: Guppies are not easy to judge male and female when they are young, and usually the first color is male fish. In addition, when observing the belly, the female fish can see the color, while the male is white. When it comes to adult fish, there are many ways to distinguish. First of all, we can observe the anal fins. The anal fins of male fish are narrow, while those of female fish are fan-shaped. Secondly, you can find fetal spots, and some are female fish. In addition, the tail of male fish will account for a larger proportion, and the overall color will be brighter.

2. Goldfish: Goldfish belongs to cold water fish, with many kinds and irregular identification methods. First of all, we can look at the body shape. Usually, the male is slender, while the female is fat and short. Moreover, the tail of male fish is thicker and looks wide and flat. When swimming, male fish are more agile and faster, while female fish swim slower.

3. Traffic lights: It is difficult to distinguish the sex of traffic light fish. Usually, males and females are slender, while females are thicker. However, this method is not very accurate, and it can only be distinguished by observing the abdominal condition during the breeding period.