Ovulation of maturing female yellow puffer, Takifugu obscrus, was induced by using single injection of human chorionic gonadotropin (HCG) or gonadotropin releasing hormone-analogue (GnRH-A) $des-Gly^{10}[D-Ala^6]$ GnRH-ethylamide plus pimozide. The response was evaluated using the fertilization and embryo-formation rate after insemination and the gonadotropin (GTH) level in blood plasma using radioimmunoassay. In the fertilization and embryo-formation, maximal effects were recorded by using 1,000 IU/kg HCG or $10;{mu}g/kg$ GnRH-A plus 5 mg/kr pimozide. Pimozide (1, 5 mg/kg) or GnRH-A treatment alone was not effective in elevation of GTH level, however combinations of these treatments were particularly effective. Injection of dopamine blocked the rapid elevation of plasma GTH levels of blood. These data suggest that yellow puffer secrete GnRH and gonadotropin-releasing-inhibiting factor during the spawning or the other period.