Given the growing water scarcity crisis, the use of unconventional water resources such as municipal wastewater has garnered attention as a sustainable an‎d cost-effective solution in aquaculture. This study aimed to assess the feasibility of rearing the ornamental fish Labidochromis caeruleus (yellow lab) in treated municipal wastewater from Shahin Shahr. An experiment was conducted over a 40-day period with six treatments: a control (0% wastewater), three wastewater concentrations (20%, 30%, an‎d 40%), an‎d two fishless treatments. Preliminary trials indicated that higher wastewater concentrations (75% an‎d 100%) were unsuitable for fish survival; therefore, the maximum applicable concentration was determined to be 40%. Throughout the experiment, physical, chemical, an‎d microbial parameters of the water were monitored at different intervals, an‎d their effects on fish growth, survival, pigmentation, an‎d microbial health were eva‎luated. The results showed that growth indices—including weight gain, specific growth rate, an‎d feed conversion ratio—were significantly higher in the control group compared to the wastewater treatments. However, the 20% wastewater treatment showed no statistically significant difference from the control, indicating comparable performance. In contrast, increasing wastewater concentration led to a decline in both growth indices an‎d survival rates, with the 40% treatment showing the lowest performance. Microbiological analysis revealed no nematode eggs in the wastewater, an‎d coliform levels in all treatments remained below the World Health Organization’s permissible limits. Skin pigmentation was eva‎luated using three methods: digital photography, reflectance spectrophotometry, an‎d carotenoid content measurement. These assessments indicated that pigmentation levels were higher in wastewater treatments—especially at 20%—compared to the control. Overall, this study demonstrated that using up to 20% treated municipal wastewater from Shahin Shahr for rearing Labidochromis caeruleus has no adverse effects on key biological parameters. Moreover, employing this water source in ornamental fish farming not only conserves freshwater resources but may also enhance certain quality traits, such as skin pigmentation. Nevertheless, higher concentrations of wastewater require further investigation an‎d stricter monitoring of its physical, chemical, an‎d microbial quality. The findings of this research may serve as a valuable step toward the development of sustainable aquaculture in water-scarce regions of the country.

سالار درافشان , اميرحسين جلالي

محمد نعمتي ورنوسفادراني

اميدوار فرهاديان , نوراله ميرغفاري