This study investigated the characteristics of the eggs and yolk sac larvae of Korean striped bitterling, Acheilognathus yamatsutae, spawned and grown In mussels. The number of eggs in the ovary was small ($358{pm}108$ SD). The eggs were oval and large, and the formation of the perivitelline space was narrow. The eggs were hatched at only 41 hours after fertilization but the hatched larvae were underdeveloped. The development of yolk projection and minute tubercles on the skin surface was notable, along with the vividly moving tail in the hatched larvae. The yolk projection and minute tubercles were disappeared upon enhancement of the motor ability of the larvae was enhanced. The formation of eyes and body pigments of the larvae was relatively delayed in comparison with that of other cyprinid larvae. After completely consuming the yolks the larvae escaped from the mussel for free swimming and exogenous feeding.