Imagine fish farms of the future that no longer depend on massive water exchange, but instead operate through self-sufficient micro-ecosystems that ensure healthy fish growth while minimizing environmental impact. This vision is becoming reality in Brazil, where groundbreaking research from the Federal University of Mato Grosso do Sul (UFMS) demonstrates the remarkable potential of biofloc technology (BFT) in cultivating South American Pacu fish ( Piaractus mesopotamicus ), paving new pathways for sustainable aquaculture.

Challenges and Opportunities in Pacu Fish Farming

The Pacu fish, also known as the silver pomfret, stands as a vital economic species in South America, prized for its rapid growth rate and delectable flesh. However, traditional Pacu farming methods typically demand substantial water resources while risking water quality degradation and environmental pollution. This urgent situation demands more eco-friendly and efficient cultivation techniques.

Biofloc Technology: A Sustainable Solution

Biofloc technology (BFT) represents an innovative aquaculture approach that cultivates microbial flocs within farming water. These flocs transform organic waste into edible biomass for fish, potentially eliminating water exchange requirements. BFT systems not only conserve water but also enhance water quality while improving fish growth rates and health indicators.

UFMS Research: BFT Application in Pacu Cultivation

To evaluate BFT's effectiveness in Pacu farming, UFMS researchers conducted comparative experiments between BFT systems and traditional recirculating aquaculture systems (RAS). The study occurred at UFMS's experimental fish farming station (20°30′04.6" S, 54°36′37.8" W) with approval from the university's animal research ethics committee (Case No.: 1.208/2022).

Researchers selected 90 juvenile Pacu fish ( Piaractus mesopotamicus ) averaging 68.86±4.43 grams in weight and 13.33±0.13 cm in standard length, dividing them between BFT and RAS systems. Throughout the experiment, scientists regularly monitored water parameters including temperature, dissolved oxygen (DO), pH, and nitrogen compounds in both systems.

Experimental Results: BFT's Superior Performance

Findings revealed BFT systems demonstrate significant advantages in water quality improvement and Pacu farming performance:

• Water Parameters: While both systems maintained similar dissolved oxygen levels ( p >0.05), BFT showed lower pH values (morning 7.64, afternoon 7.68) compared to RAS (morning 7.86, afternoon 7.90) ( p <0.05). Total ammonia nitrogen (TAN) levels remained comparable between systems (p>0.05), though RAS consistently recorded higher temperatures across daily measurements ( p <0.05).
• Growth Performance: Pacu in BFT systems exhibited accelerated growth rates and superior feed conversion ratios, indicating BFT enhances both water conditions and farming efficiency.
• Health Indicators: BFT-cultivated Pacu demonstrated stronger immune responses and disease resistance, likely attributable to the system's rich microbial communities that promote intestinal health and immune function.

The Science Behind BFT: Microbial Floc Dynamics

BFT's efficacy stems from microbial flocs—complex aggregates of bacteria, algae, protozoa, and organic particles. These flocs absorb organic waste and nitrogen compounds, converting them into edible biomass that simultaneously purifies water and provides natural nutrition.

Furthermore, microbial flocs generate bioactive compounds including enzymes, vitamins, and antibiotics that stimulate fish growth, bolster immunity, and enhance disease resistance. Thus, BFT systems function as complete micro-ecosystems that create optimal growing environments.

Future Applications: Sustainable Aquaculture's Horizon

As an eco-conscious aquaculture solution, BFT technology holds vast potential for diverse species including fish, shrimp, and shellfish—particularly in intensive farming operations. BFT adoption could substantially reduce water consumption, environmental contamination, and operational costs while improving production efficiency.

Global interest in BFT continues expanding, with mounting evidence demonstrating its capacity to enhance water quality, farming productivity, and food safety while reducing antibiotic dependence. Consequently, BFT emerges as a pivotal future direction for aquaculture development.

Current Limitations and Research Frontiers

Despite its advantages, BFT technology presents certain challenges:

• System operation requires technical expertise for water parameter monitoring, carbon-nitrogen ratio adjustment, and microbial floc management
• Initial investments for bioreactors, aeration equipment, and monitoring instruments can prove substantial
• Complex microbial communities remain vulnerable to environmental fluctuations that may destabilize systems

Future research should prioritize:

• System design optimization through improved bioreactors, aeration methods, and smart control mechanisms
• High-efficiency microbial strain selection to enhance waste degradation capabilities
• Comprehensive studies on BFT's effects on fish intestinal health and immune function
• Cost reduction strategies via affordable carbon sources and simplified monitoring equipment

Conclusion: A Promising Future for Pacu Farming

The UFMS study establishes BFT technology's significant advantages in Pacu cultivation—improving water quality, production efficiency, and fish health. As a sustainable aquaculture solution, BFT offers new developmental opportunities for Pacu farming. Through continued system optimization, cost reduction, and technology dissemination, BFT stands poised to play an increasingly vital role in aquaculture's future.

These findings support in situ biofloc implementation to enhance efficiency and strengthen juvenile Pacu production. Complementary research by Adineh et al. (2019), El-Sayed (2021), Khanjani et al. (2024), Shourbela et al. (2021), and Zhang et al. (2018) further validates BFT's value in aquaculture—particularly for Nile tilapia and carp farming—where it reduces or eliminates water exchange while maintaining water quality and health standards. This study underscores biofloc technology's potential as a sustainable, high-value P. mesopotamicus farming system that enhances growth performance, ensures superior water conditions, increases production efficiency, and strengthens juvenile fish immune responses.