<p>Biofloc technology (BFT) is a promising approach for sustainable aquaculture; however, challenges such as solid accumulation and water quality fluctuations remain. This study evaluated the synergistic effects of integrating substrates for periphyton-based aquaculture (PBAT) and polyculture with a detritivorous fish on the intensive culture of white cachama (<i>Piaractus orinoquensis</i>). A 60-day trial was conducted under a completely randomized design with three treatments in triplicate, all in BFT with a C:N ratio of 15:1: (C) cachama monoculture; (CB) cachama polyculture with bocachico (<i>Prochilodus mariae</i>); and (CBS) cachama–bocachico polyculture with bamboo substrates (BFT–PBAT system). Water quality, solids dynamics, microalgal community, and zootechnical performance were monitored. The CBS treatment showed significantly improved water quality, with lower nitrite and nitrate concentrations and higher, more stable alkalinity (<i>p</i> &lt; 0.001). The final sludge-to-biomass ratio was significantly lower in CBS (0.15) than in C (0.23) (<i>p</i> = 0.045). Cachama in the CBS treatment reached a significantly higher final weight (28.66&#xa0;g) and specific growth rate (6.2% day⁻¹) than those in the CB treatment (<i>p</i> = 0.02). Growth was also higher than in the C treatment, though not statistically significant. The microalgal community structure was primarily shaped by culture time rather than by treatment (<i>p</i> = 0.001), showing a temporal succession from Chlorophyceae to Cyanophyceae. In conclusion, the integration of periphyton substrates into BFT polyculture was an effective strategy for improving water quality, optimizing solid management, and enhancing the growth performance of <i>P. orinoquensis</i>. The addition of bocachico alone did not yield significant zootechnical improvements over cachama monoculture.</p>