LAJU PERTUMBUHAN HARIAN DAN SINTASAN IKAN GURAMI ( Osphronemus goramy ) DENGAN SISTEM BIOFLOK YANG DIBERI SUMBER KARBON DENGAN PERSENTASE YANG BERBEDA

This study aimed to analyze the effect of adding tapioca flour as a carbon source in a biofloc system on the growth performance and survival rate of gouramy fish (Osphronemus goramy). The study was motivated by the relatively slow growth rate of gouramy fish and the low feed utilization efficiency caused by declining water quality in conventional aquaculture systems. Biofloc technology was applied as an alternative culture system because it is capable of improving water quality and providing additional natural nutrients through the activity of heterotrophic microorganisms.
The research was conducted in December 2025 at the Integrated Science Laboratory, Faculty of Science and Technology, Nahdlatul Ulama University of Purwokerto, using an experimental method with a Completely Randomized Design (CRD). The treatments consisted of four levels of tapioca flour addition, namely 0% (control), 5%, 10%, and 15%, with three replications for each treatment. The observed parameters included absolute weight gain, absolute length gain, Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), feed efficiency, survival rate (SR), and water quality parameters. Data were analyzed statistically using Analysis of Variance (ANOVA) followed by the Least Significant Difference (LSD) test.
The results showed that the addition of tapioca flour in the biofloc system affected the growth performance of gouramy fish. The best treatment was obtained at 5% tapioca flour addition, which produced the highest absolute weight gain of 8.67 g. Higher concentrations of tapioca flour (10% and 15%) resulted in lower growth performance, presumably due to excessive organic matter accumulation that reduced water quality and disturbed fish metabolism. Overall, the addition of 5% tapioca flour in the biofloc system was considered the most effective treatment for improving the growth and culture efficiency of gouramy fish.
Keywords: biofloc system, gouramy fish (Osphronemus goramy), growth, tapioca flour, survival rate