Impact of probiotics mixture as a water additive on water quality, growth performance and survival of <em>Catla catla</em> fry

The main objective of this study was to assess theimpact of a commercial probiotic as a water additive on the survival, growth performance, and water quality of C. catla. A field trial was conducted for 66 days. About 360 C. catla fry (0.25 ± 0.01 g) were distributed randomly among 12 quadruplicate-designed cemented tanks, each containing 30 healthy fish in 0.15 m3 of water. Control tanks were not treatedwith probiotics while the treatment tanks received 0.012 g m-2 week-1 and 0.03 g m-2 week-1 of the probiotic. Principal Component Analysis was carried out to identify key water quality factors. One-way ANOVA followed by Tukey’s test was used to compare statistical differences. The results showed that adding probiotics significantly decreased ammonia concentration (p < 0.05). No significant differences were found in water temperature, total dissolved solids, pH, and electrical conductivity between treatments and control. The fish in tanks treated with probiotics showed a substantial increase in survival rate (p < 0.05), with the highest value of 92 ± 1.5%.The survival of C. catla fry was enhanced when a high dosage of 0.03 g m-2 week-1 was administered. Despite the positive impact on survival, probiotic treatment did not influence the overall growth performance.