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)

Biofloc technology (BFT) has become an agenda to meet the need for protein food and 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. The study was conducted with control and two different C/N ratios (15:1 and 20:1). 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. The specific growth rate and weight gain were observed to be significantly higher at a high C/N ratio. The feed conversion ratio was lower in the C/N 20 group, indicating a more efficient feed utilization. According to the liver histological results, the vacuolization symptom is more severe in BFT groups. Considering all the results, the suitability of C. auratus cultivation in the BFT system with a C/N ratio of 20 was proven according to nine different evaluation criteria. In conclusion, rearing C. auratus in BFT systems is advised due to its economic and ecological benefits.