Biofloc technology is the "blue revolution" in aquaculture and a recent technology for enhancing the utilization of feed wastes in aquaculture. The effects of different biofloc systems on growth rates and histological changes in the intestines of grass carp (Ctenopharyngodon idella) fingerlings were investigated using three carbon sources: molas, starch, and wheat flour. over a period of three months. Four experimental groups, control, molas, starch, and wheat flour, were set in parallel triplicates and growth performance parameters, including final body weight, total weight gain, survival rate, specific growth rate (SGR), and feed conversion ratio (FCR), The current findings demonstrate that all diet-treated groups exhibit significant changes in the measured growth parameters (p< 0.05). The lowest final weight (77.3 g), weight gain (75.6 g), and SGR (2.5%/day) were achieved for fish raised on a wheat flour-supported diet. Histo-morphometric analysis of the anterior and posterior segments of the intestine showed a significant increase in the length of the intestine. intestinal villi width as well as an increase in the number of goblet cells in the BFT groups compared to the control. In summary fish farming with the BFT using feed supplemented with various carbon sources might be very beneficial to fish farmers because it can reduce feed costs and improve yield.