The Potential of Ornamental Fish Culture in Biofloc Technology with Different C/N Ratio and Multi-Criteria Decision Making Model: An Example of Goldfish (Carassius auratus)

Abstract Biofloc technology (BFT) has become an agenda not only to meet the need for protein food but also for ornamental aquaculture with the increasing interest in sustainable aquaculture. In this context, the current study focused on BFT for ornamental goldfish (Carassius auratus), which has commercial value. In the study conducted with control and two different C/N ratios (15:1 and 20:1), nitrogen cycle occurred rapidly in BFT groups. On the other hand, increasing the C/N ratio had a positive effect on total suspended solids and total bacteria count in the culture water. In terms of growth performance, specific growth rate and weight gain were observed to be significantly higher at high C/N ratio. Feed conversion ratio showed lower results for the C/N 20 group. According to the liver histological results, the vacuolization symptom is more severe in BFT groups. Considering all the results, the suitability of C. auratuscultivation in the BFT system with a C/N ratio of 20 was proven according to nine different evaluation criteria. In conclusion, the cultivation of C. auratus in BFT systems is recommended both economically and ecologically.