Managing a biofloc fish tank

Posted by Mohan Tarp on April 19th, 2021

It is very important to understand that complete water management is necessary to maintain and manage the proper fish health in biofloc technology. Creating a biotech fish tank that is compartmentalized can offer greater control to fish farmers and maintain healthier fish dynamics. In some cases, it has been seen that biofloc farming has disturbed shrimp and fish health as there is a general misappropriate handling of suspended solids in the water. Therefore farmers require knowledge in microbial dynamics of biofloc fish tanks.

The concept

The idea behind biofloc technology was to enhance water quality by balancing carbon and nitrogen in the system and recycling waste nutrients such as nitrogen into microbial biomass for allowing the beneficial bacteria to colonize in the culture water. This technology began in the 1990s for fish and shrimp farming. The tanks maintained higher carbon to nitrogen ratio stimulating the culture of heterogeneous bacteria, the microbes that break organic carbon from the environment. This bacterial growth in the biofloc fish tank consumed nitrogenous fish waste and toxic metabolites before they were eaten by the propagated fish species, reducing the environmental footprints of both production and feed cost.

Advantages

The introduction of biofloc fish tank has proved to be beneficial in numerous ways. The cultured bacterial flocs are protein-rich and are a nutritious and vitamin-enriched source of food for both fish and shrimps. The water quality also improved as the nitrogen toxins are immobilized. Productivity has greatly improved in comparison to regular aquaculture fish tank techniques. The mortality rate within the propagated species has also gone down. The convenience of the biofloc fish tank is many. It allows zero water exchange and relies on land usage, the environmental production impact is marginal and with little or no water inputs the pollution level is also minimized helping in establishing greater biosecurity at the time of production.

Problems 

However, some disadvantages have also been noted. The energy cost increases due to the mix of aerating culture water. The biofloc ponds need to manage nitrate accumulation and maintain alkalinity level in a healthy range. Also solid suspended particles need to be managed to ensure that the fish and shrimp do not succumb to environmental stress. Some studies have revealed that microbal flocs have a probiotic effect and might contain a higher vibrio count which could expose fish to high-risk disease.

Conclusion

Though researchers have a vivid concept of how a biofloc fish tank should be managed, the producers have a long way to go before they master the farming concepts fully. Nevertheless, this is the ideal farming concept for bottom-dwelling species like tilapia. With the shifting bacterial load in the water, the fish gets resistant to environmental challenges. However, this applies to the more hardy varieties. The compartmental designs offer farmers more control and translate to healthier yields.