The effect of various doses of Gonazon™ was investigated on ovulation induction and the optimal dose (32 μg/kg B.W.) was subsequently compared to the whole control population in terms of differences in reproductive traits, embryonic development and fry quality (growth and malformation). No differences were observed between the treated and the control groups for fecundity, egg weight and rates of fertilisation, eyed eggs, hatched eggs and swimming fry. Mean weight of juveniles was not different. Incidence of malformations was unaffected by treatment.