This study evaluated the effects of different carbon sources on the larval rearing of the mud crab (Scylla paramamosain) using biofloc technology. The experiment comprised five treatments, three replicates each with different carbon sources: (i) no carbon addition (control), (ii) granulated sugar, (iii) rice flour, (iv) wheat flour and (v) corn starch. Experimental larvae at the Zoea 1 stage were stocked in 250-L tanks at a density of 200 ind L⁻¹. Carbon sources were supplemented daily, starting from the Zoea 3 stage at a C:N ratio of 20. The results indicated that total ammonia nitrogen, nitrite, total bacterial density and Vibrio counts were significantly lower in carbon-supplemented biofloc treatments when compared to the control (p < 0.05). Conversely, larval stage index, growth in length, survival rate and crab 1 yield were significantly higher in biofloc treatments (p < 0.05). The rice flour treatment achieved the highest survival rate (9.89±0.17%) and Crab 1 yield (19,772±337 ind m⁻³), showing significant superiority over all other treatments (p < 0.05). Therefore, rice flour is recommended as the most suitable carbon source for biofloc-based mud crab larval rearing.
