Sexual maturity of the redtail is slow, and the gonads are mature only in the 4-year-old fish with a body length of 26 centimeters. The spawning period is from June to July, and floating eggs are laid in large rivers. The average amount of pregnant eggs is 36,000, the egg grain is larger, the yolk diameter of about 1, 25 millimeters. Generally, the body length of 1-year-old fish is about 7,5 centimeters, 2-year-old fish is 13 centimeters, 3-year-old fish is 19,5 centimeters, 4-year-old fish is 26 centimeters, 5-year-old fish is 31 centimeters.