Effects of Immediate Oxygen Supplementation (Sodium Carbonate and Hydrogen Peroxide) on Water Quality Parameters, Behavioural Responses and Survival of <i>Puntius sophore</i> Fingerlings

The intensification of aqua-farming practices has increased the need for a constant oxygen supply to avert oxygen depletion and unexpected fish mortality in captivity. This study assessed the effects of bio-ox (10% sodium carbonate and hydrogen peroxide) as an immediate oxygen booster on water quality, behavioural patterns and cumulative per cent survival (CPS) of Puntius sophore (3.50 ± 0.13 g) in a controlled rearing environment. The completely randomized design comprised four treatments: a control group (T1) without bio-ox and three experimental groups (T2, T3 and T4) treated with 1, 3 and 5 g of bio-ox per 70 L of water, respectively. Bio-ox was applied at the start and at 36 h, with observations recorded every 6 h. Initially, water quality parameters showed no significant differences (p > 0.05) among treatments. Post-supplementation, bio-ox levels significantly influenced (p < 0.05) hydrological variables, including conductivity, total dissolved solid (TDS), total ammonia nitrogen (TAN), dissolved oxygen (DO) and pH. Conductivity and TDS increased with higher bio-ox dosages, whereas TAN levels were significantly lower (p < 0.05) in all bio-ox-treated groups compared to the control, with no significant differences among treated groups at 42, 48 and 54 h. DO peaked at 11.90 ± 0.10 mg/L at 60 h in T4, whereas T2 maintained optimal levels. The pH also varied significantly (p < 0.05), reaching a maximum of 9.23 ± 0.01 at 36 h in T4. Temperature, water pressure and salinity remained unaffected (p > 0.05). Behavioural observations indicated minimal abnormalities in T2, whereas higher bio-ox doses (T3 and T4) resulted in pronounced changes, including hyperactivity, abnormal swimming and convulsions. Kaplan-Meier survival analysis revealed significant differences among treatments, with T2 showed the highest CPS of 66.7%, which was significantly greater than that of T3 (26.7%, p = 0.026) and T4 (13.3%, p = 0.007). The control group T1 (40%) exhibited intermediate survival rates, which were not significantly different from any treatment groups. These findings suggest that bio-ox at 1 g/70 L (T2) provides optimal conditions, stabilizing fish behaviour and significantly improving survival compared to higher doses.