Despite the resemblance between GnRH3 and GnRH1 peptides and their neurons, and though the loss of the hypophysiotropic GnRH1 in medaka (gnrh1−/−) results in infertility in females [5], gnrh3−/− zebrafish maintain normal fertility [23,24]. The gene discussed is GNRH1; the disease is Infertility.