We studied the time of initial sexual maturity and the fecundity of the goldfish Carassius auratus under semi-controlled conditions. During the study the water temperature fluctuated from 21 to 30°C, the pH between 7 and 8, and the dissolved oxygen between 5.5 and 7 ppm. Sixty days old juvenile fish received prophylactic treatments of brackish water (15 ‰) and methylene blue baths (1 %), and they were fed with live Daphnia magna. The initial sexual maturity occurred between 225 and 233 days of captivity. Mean absolute fecundity was 2 347 (± 302.2 SD) ova per gonad, and mean relative fecundity was 63.44 eggs/g fish weight. Gonadosomatic index was between 7.5 and 9.0. Our data will allow ornamental fish producers to calculate the time of initial maturity and fecundity for this species.