Vol. 9, Issue 10, Part F (2025)

An experiment was conducted for a period of 90 days to evaluate the effect of carbon sources on growth and survival of Cyprinus rubrofuscus in biofloc system. The experiment was designed following completely randomised design with one control and three treatments in triplicate viz., T₁ (tapioca starch), T₂ (jaggery), T₃ (cornstarch) along with T₀ (control: without carbon addition). The weight of Cyprinus rubrofuscus ranged from 3.55 g to 3.59 g was distributed randomly to all 12 tanks at a stocking density of 10 nos. per 200-liter capacity tank. The carbon-nitrogen ratio was maintained 20:1 throughout the experimental period in biofloc tanks. No carbon source was added in control with periodical water exchange and siphoning. The mean body weight of fish during the stocking was 3.56±0.01 g, 3.57±0.02 g, 3.57±0.02 g and 3.56±0.02 g respectively in T₀, T₁, T₂ and T₃. At the end of the experiment, the highest growth reported in jaggery treated tank i.e.T₂ (19.87±0.54 g) and the lowest in control T₀ (10.26±0.59 g). The higher average daily growth was recorded from T₂ (0.18 g), followed by T₃ (0.17 g), T₁ (0.11 g) and T₀ (0.07 g) at 90 days of culture. Significant difference in weight gain was observed between the control and treatments during the experimental period (p<0.05). The SGR showed, biofloc grown Cyprinus rubrofuscus was significantly better than that of the control (p<0.05). Feed conversion ratio and survival rate of all biofloc treated tank was significantly better than the control (p<0.05). Among the different carbon sources used, the highest weight gain was observed in jaggery based biofloc treatment. So, the jaggery-based biofloc system is a better carbon source than the cornstarch and tapioca starch for rearing of Cyprinus rubrofuscus.