According to the morphological and physiological characteristics, the developmental period from the fertilization to the larval fish just produced is divided into eight stages. Unfertilizated eggs are long ellipsoid in shape with one being bigger and the other smallar. The cytoplasm is gradually accumulated at the animal pole after fertilization. These eggs change into spherical shape two hours and forty minutes after fertilization at the temperature of about 28-29℃. The process of the cleavage and the gastrulation is the same as that of the ordinary fish. The oil globules are gradually accumulated towards the animal pole before gastrulation and then slowly move to the vegetable pole. In six days after fertilization, the length of the tail gets slightly longer than the body.The embryo is hatched out by another half day or one day. During the same period, the caudal-fin membrane is also formed, which is gradually degenerated on the second day after the larva is released. The incubation period is 19days at 22.5士0.5℃,16 days at 24 士0.5℃ and 11 days at 28.5 +0.5℃. The most optimum temperature range for its brooding is roughly from26°Cto30°C.