Enhancing goldfish reproduction: Role of substrates in optimizing fertilization and hatching rates under controlled conditions

Ornamental fish production is significantly impacted by whether fish spawn naturally under controlled conditions. Therefore, goldfish (Carassius auratus) were allowed to breed naturally using various types of substrates to investigate their effects on ovulation, fertilization, and hatching rates in an experimental setup. The goldfish were subjected to five different substrate treatments: T1 (water hyacinth), T2 (jute rope), T3 (polythene), T4 (net), and T5 (no substrate). The optimal pH and dissolved oxygen levels for goldfish spawning were found to be 7.14 to 7.24 and 5.65 to 6.22 mg/L, respectively. Results indicated that the highest number of eggs (356.66±40) was observed in the polythene substrate (T3), while no eggs were found in the absence of substrate (T5). The polythene substrate also yielded the highest fertilization rate (93%) and hatching rate (95.01%). Notably, goldfish exhibited no spawning behavior without any substrate, suggesting that substrate may act as both a spawning substrate and an essential cue for ovulation in goldfish. Furthermore, the study's findings support the recommendation of goldfish as substrate breeders. This research offers valuable insights for small-scale fish farmers, entrepreneurs, and hatchery owners looking to enhance goldfish spawning techniques in aquarium settings.