Influence of Probiotics on Early Maturation and Reproduction of the Goldfish (Carassius auratus) in Hatchery Condition in Tropical Region

   The goldfish (Carassius auratus) is a highly valued ornamental species in the global aquaculture industry. However, optimizing early maturation and reproductive performance remains challenging, especially in tropical regions. Probiotics, which are live microorganisms that promote gut health, immune function, and overall growth, have emerged as a potential tool for enhancing reproductive outcomes in aquaculture. This study explored the influence of probiotics on the early maturation and reproductive success of goldfish under tropical hatchery conditions. Probiotics were incorporated into the diet at levels of 1, 2, and 3 grams per kilogram of formulated feed. Eight-month-old goldfish fry were fed these probiotic-supplemented diets for 2 months before being subjected to natural breeding in controlled environments. Natural breeding was observed in 10-month-old goldfish fed probiotics. The results indicated that higher temperatures (28°C) combined with probiotic supplementation significantly reduced maturation time and improved breeding performance compared to the control group. Among the different probiotic levels tested, the diet containing 2 grams per kilogram produced the best outcomes, with increased relative fecundity (31.15%), fertilization rates (85.68%), and hatching rates (82.35%). This finding aims to offer new insights into probiotic applications for boosting breeding efficiency and contributing to more sustainable ornamental fish production in tropical regions. The enhanced early maturation and breeding performance offer valuable opportunities for entrepreneurship, foreign currency earnings, and financial security in fish culture sector of Bangladesh.