Effect of Floc Formation Time on the Growth of Catfish (Pangasius hypophthalmus) in a Biofloc System

Striped catfish (Pangasius hypophthalmus) is a high-value freshwater aquaculture commodity, yet the success of biofloc systems strongly depends on floc maturity prior to stocking. This study analyzed the effect of floc formation time (3, 5, and 7 days) on the growth, feed efficiency, and survival of striped catfish in a biofloc system using a one-factor completely randomized design with three replicate ponds per treatment as the statistical unit. Fry were reared for 60 days at a density of 50 fry/pond. ANOVA showed that floc formation time had a highly significant effect on absolute weight gain (F=210.625; p=0.000) and absolute length gain (F=574.586; p=0.000), with the highest values in P3 (7 days): 16.00 g and 10.30 cm; Duncan's test placed all three treatments in distinct groups. Because the data did not meet the normality assumption, feed conversion ratio and survival rate were analyzed using the Kruskal-Wallis test, which showed significant differences among treatments (FCR: H=6.543; P=0.038; SR: H=6.108; P=0.047), with the lowest FCR (0.65) and highest SR (89.33%) in P3. In contrast, floc formation time had no significant effect on specific growth rate (F=0.106; p=0.901), which ranged from 1.75–1.77%/day across treatments. Floc volume increased consistently from 5.2 mL/L (P1) to 15.4 mL/L (P3), paralleling the improvement in growth and survival. All water quality parameters (temperature 26.46–27.21°C, pH 6.88–7.56, DO 4.40–4.62 mg/L, ammonia 0.16–0.28 mg/L) remained within the range required by Indonesian National Standard SNI 01-6483.5-2002 for pond grow-out of striped catfish. Under the conditions of this study, a 7-day floc formation period was the most effective for supporting growth, feed efficiency, and survival of striped catfish in a biofloc system.