Biofloc the changing approach to fish feed

Posted by Mohan Tarp on May 21st, 2021

Biofloc technology is considered the new blue revolution as it allows nutrients to be continuously recycled in the biofloc tank or biofloc fish tank. The culture medium minimizes the exchange of water. It is an environmentally friendly aquaculture technique of in-situ microorganism production.

Biofloc acts as a water treatment remedy while at the same time utilizes the microbial process within the pond and food resource for the cultured organism in the water. This process is also called active suspension ponds or heterotrophic ponds. 

How does the process work

• The wastewater treatment biofloc system has gained a lot of significance for its approach to aquaculture.
• The technique requires maintaining the CN ratio by enriching the water with carbohydrates, thus enabling the production of high-quality single-cell microbial protein.
• The nitrogenous waste from the heterotrophic microbial growth is used by the culture species as feed and this helps in controlling the water quality that works as a bioreactor.
• The toxic nitrogen is immobilized at a higher rate in biofloc because the growth rate of the microbial product is 10 times greater than the autotrophic nitrifying bacteria.
• Biofloc is a protein-rich life feed that is a result of the conservation of unused feed and excreta that converts into natural food in a cultured system that is exposed to sunlight and aeration.
• The block is held together by a loose matrix mucus secreted by bacteria in an electrostatic attraction. You can see large flocs with the naked eye while the microscopic flocs vary from 200 microns. 
• It is a good source of vitamin and minerals and is Phosphorus enriched. With an effect similar to probiotics, dried biofloc can replace a fish meal or soya bean as a feed. The dry weight has 25-50% protein and 0.5 -15% fat.

The advantages of a Biofloc fish tank

• Biofloc culture feed is eco-friendly.
• It reduces environmental impact.
• Makes judicious usage of land and water.
• There is a zero or minimum water exchange involved.
• Enabling feed conservation in the culture system enhances fish survival rate and growth performance.
• Provides higher biosecurity.
• Mitigates water pollution and the spread of pathogens.
• Reduces cost and utilizes protein-rich feed.
• Helps in procuring cheap and enriched food for fish.

Fish that can derive direct nutrition from the consumption of flock are the species that are cultured in the biofloc fish tank. Species that can tolerate high solid concentration in water and can live in poor water quality are most suitable for a biofloc fish tank. Air-breathing fish like singhi, magur, pabda, koi, pangasuisaczn live in this environment. Breeding fish like common carp, Rohu, tilapia milkfish shellfish like vannamei, tiger prawn also do well in this kind of environment.