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Recirculating Aquaculture System (RAS)

Recirculating Aquaculture System is a filtration process in fish farms, mostly connected to Pond Aquaculture such as Tarpaulin, Concrete, Plastic, Fiberglass, and other types of Pond aquaculture.

This system filters the insoluble waste from the fish, leftover feeds, and other particles that could compromise the health of the fish stocked.

How RAS (This particular setup) works.

The core of the Recirculating Aquaculture System involves a network of  PVC pipes varying in sizes. It could be 1”, 1/2”, and any type. These pipes are strategically perforated, and laid beneath the fish pond. 

This forms what we call Moving Bed Biofilter (MBB). The MBB serves to collect insoluble waste from the fish pond, directing it towards a sedimentation filter for further processing.

Mesh Sieves or filter packs are put under the button of the sedimentation filter. This will always keep the waste under to be flashed out. And only allow filtered water to pass through.

After the Sieve or filter packs take the waste, the water comes out through it onto the top of the container. At the top of the container, a submersible water pump is there. This pump collects and pumps the water back to the pond again.

As the water falls back to the fish pond, it adds oxygen to the fish pond again.

This process also removes harmful chemicals such as ammonia from the fish pond which is dangerous to the fish.

There is another submersible water pump inside the fish pond whose purpose is to circulate the water and add more oxygen to the pump.

This process continues 24/7.

Moving Bed Biofilter (MBB)

Moving Bed Biofilter (MBB)

sedimentation filter

sedimentation filter

Importance of Recirculating Aquaculture System (RAS)

  1. It filters the water by removing insoluble waste and also ammonia from the fish pond
  2. The circulation process adds more oxygen to the fish pond
  3. Conducive for the fish since they always hung around the system.
  4. No need to always change the water of the fish pond therefore preserving water in the pond. This is possible because the water doesn’t become dirty easily since the waste is removed.
  5. It makes the place odorless therefore making it friendly for cities and other residential areas.

The setup can also be used to empower aquaponics therefore killing two birds with one stone. That is serving a dual purpose.


  1. Is costly since you need to buy submersible water pumps, containers, sedimentation filters, PVC pipes, and others.
  2. There should always be electricity therefore it can’t work where there is no electricity source.
  3. Is also risky because we all know water is a good conductor of electricity so you are likely to receive electricity shocks. I have received electricity shocks myself on my farm already.
  4. Requires some level of technological knowledge to operate since it involves pumps. So, you need to hire someone who can manage that or learn and do it yourself.
  5. Is laborious because you need to clean the filter and remove the insoluble waste almost every day.


Despite its limitations, is a good system for large or commercial fish farming since it maximises water usage, minimises the smell of your pond, increases the oxygen level of the pond, and others.

RAS system is a technical issue that needs a technical expert. Therefore consult an aquaculture consultant on recommendations on the RAS system NOW


Recirculating Aquaculture Systems offers a promising solution for sustainable fish farming, offering a balance between environmental stewardship and economic viability. With careful planning, investment, and management, RAS can pave the way towards a more resilient and profitable aquaculture industry.

RAS is a technical issue and need technical expert

Abdul Aziz Issah
Abdul Aziz Issah

With a solid background in fish farm management, I’ve successfully established and operated a flourishing fish farm for about a year now. Over this period, I have gained invaluable experience that I am eager to share with fish farmers, whether they are beginners or seasoned experts.

This blog is dedicated to empowering fish farmers to maximize their profits through the pool of knowledge and practical insights I will be sharing. Whether you are venturing into fish farming for commercial purposes or as a hobby, you have come to the right place. I am here to guide you every step of the way.

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