(A) the difference between external forms:
(1) Body size difference: Generally speaking, male goldfish are slightly longer, while female goldfish are slightly shorter and rounder. The abdomen of female fish is larger than that of male fish during spawning.
(2) The difference of tail stalk: the male fish is slightly stronger than the female fish.
(3) Difference of pectoral fin: Careful observation shows that the male fish is slightly longer, and the first fin of pectoral fin is thicker and harder; The female fish is short and round, and the first fin of pectoral fin is not too hard.
(4) The difference of spawning holes: From the belly up, the spawning holes of male fish are small, long and narrow and concave; The spawning hole of female fish is larger, slightly round and protruding outward.
(2) Color difference: The body color of male and female goldfish is slightly different. Males are usually brightly colored, while females are slightly lighter. During the reproductive and developmental period, males are more brightly colored.
(3) Touch and feeling: Hold the fish's abdomen gently with your hands. The middle finger and ring finger feel that the male fish's abdomen has obvious hard lines, and the female fish's abdomen is soft. When walking by the fish pond, the male fish swims fast and agile, while the female fish moves slowly.
(4) Idyllization: With the increase of temperature, goldfish will have a second characteristic-idolization of spawning period, which is the easiest and most accurate time to identify the sex of goldfish and the easiest method to master. Male fish occasionally appear on the first thorn of pectoral fin and the edge of gill cover. Many times, there are idolize on each fin of the whole pectoral fin, and the front end is obvious, so you can only observe it carefully at the back. This rough little white dot is idolized. Using the above identification methods, we must rely on years of feeding experience and careful observation at ordinary times to accurately identify the male and female goldfish.