The first thing is to observe the body shape. The female fish is short and round, while the male fish is slender. If the breeds are high-headed, tiger-headed, lion-headed, etc., their heads can be observed. The sarcoma of female fish is low and not full, while that of male fish is high and full. Secondly, the gill cover was observed. In the breeding period, the gill cover of male fish had sparse protruding punctate idolize. The female fish's pectoral fin is short and round, while the male fish's pectoral fin is long and the tail end is sharp, and idolize is also found on the pectoral fin during the breeding period. The female fish's reproductive hole is round and slightly larger, pear-shaped, with the stalk end forward and close to the pectoral fin, slightly protruding outward; The male fish is slightly smaller in prismatic shape, such as jujube pit, with sharp ends, swollen middle, flat and slightly concave. There is also the female fish in the breeding period swimming slowly and responding slowly; Male fish swim lively and chase sensitively. Finally, the abdomen of the fish is observed. The abdomen of the female fish is soft, from the abdomen to the anus, the hard edge is not obvious, and the abdomen is swollen and rounded during the breeding period; The abdomen of male fish is hard, with obvious hard edges from abdomen to anus, and does not swell during breeding period. However, this cannot be misjudged, because some goldfish species, regardless of the male and female abdomen, are swollen and rounded, so we must carefully distinguish them when identifying them.

(1) The methods of male and female identification of the four major fishes are basically the same, mainly from pectoral fins.

(2) The mature age and weight of domestic fish are quite different between the north and the south of China. The general rule is: the south matures earlier and the individuals are smaller; In the north, the maturity is late and the individual is large; Male fish is one year earlier than female fish.

(3) The ratio of male and female mating should be 1: 1 ~ 1.5, that is, the male fish is slightly more than the female fish.

(comparison of male and female characteristics of silver carp and bighead carp)

characteristics of a male fish

characteristics of silver carp male fish

1. On several fins in front of pectoral fin, especially on the first fin, there is a row of bony tiny comb teeth, which feel rough and prickly when touched by hand. These comb teeth will not disappear after they are generated.

2. The abdomen is small. When sexual maturity, semen flows out of the genital foramen by gently pressing the testis.

characteristics of bighead carp male fish

1. The upper edges of several fins in front of pectoral fins are each provided with backward-inclined front mouths, and touching them forward with hands

feels like cutting hands.

2. The abdomen is small. When sexual maturity, semen flows out of the genital foramen by gently pressing the testis.

characteristics of grass carp male fish

1. pectoral fins are thick and long, and naturally open into a sharp knife shape.

2. When the gonads are well developed in the reproductive season, idolize appears on the inner side of pectoral fin and gill cover, and it feels rough when touched by hand.

3. During sexual maturity, there is semen flowing from the genital foramen when the testis is lightly pressed.

The characteristics of male herring

are basically the same as those of grass carp. In the reproductive season, when the gonads are well developed, there are not only < P > idolize on the inner side of pectoral fin and gill cover, but also the characteristics of forcing stars < P > two females < P > silver carp females

1. Only a small part of the distal part of pectoral fin has these comb teeth, and the rest < P > are smooth.

2. The abdomen is large and soft, the stoma is often slightly prominent, and sometimes it is reddish.

female characteristics of bighead carp

1. The pectoral fin is smooth and there is no feeling of cutting hands.

2. The abdomen is swollen and soft, and the stoma is often slightly prominent, sometimes slightly ruddy.

female characteristics of grass carp

1. The pectoral fins are thin and short, and naturally open slightly in a fan shape.

2. Generally, there is no idolize, or there is a small amount of idolize on the pectoral fin.

3. The abdomen is bigger and softer than the male, but generally smaller than the female of silver carp and bighead carp. The pectoral fin is smooth, without idolize

The female characteristics of herring

are basically the same as grass carp. The pectoral fin is smooth without idolize.