Biofloc fish farming

About the business

Stocking fish densely in tarpaulin or cement tanks, running motors to keep oxygen up and building a colony of useful bacteria to hold the water. Facebook and YouTube are full of videos about it right now. This page is the other side. Abdur Rahman of Thakurgaon trained in Narayanganj and started with two tanks, tarpaulin, fingerlings and electrical gear, about Tk 4 lakh in all. He stocked koi first; the fingerlings were poor and 18,000 to 19,000 of them died. Then a sudden flood, with no drainage in place, carried much of the stock away. He then stocked tilapia, and poor fingerlings and a low fish price cost him again - Tk 1.8 lakh on fish alone across the two rounds, on top of very high electricity bills from the motors. In the end he sold Tk 60,000 of fish, shut the operation and sold off the equipment. District fisheries officer Khaliduzzaman says people start from a YouTube video or from what somebody told them, meet reality and lose money; anyone who cannot keep oxygen, ammonia and the bacteria under control drops out. Raihan Hossain, who made it work, has one piece of advice: when the power goes the oxygen stops, so a generator or a battery has to be in place beforehand. This is not a fish business. It is an electricity and fingerling business, and if either goes wrong nothing else matters.

Unit economics

What you need to start

• Meters for pH, TDS, oxygen and temperature. Oxygen has to stay between 6 and 10 and temperature between 25 and 30, and there is no way to know without measuring.Equipment
• A generator or battery, which is not a backup but the main piece of equipment. When the power goes the oxygen stops, so the successful grower's advice is to have one in place from the start.Equipment
• Tanks and tarpaulin, an oxygen machine and nano tubes. These sell at widely varying prices and have to be bought carefully; complaints of being cheated are common in this trade.Equipment
• Trade licence from the union parishad, municipality or city corporation: form Tk 10, licence book Tk 50, standard tax Tk 30, stamp Tk 150-300, licence fee Tk 100-60,000 by trade type. Needed for a bank account or a loan in the farm's name.Licence
• Understanding the water chemistry - pH, TDS, ammonia and the balance of useful bacteria. In the district fisheries officer's words, farmers drop out exactly when they cannot control these. It is not learnable from YouTube.Skill
• Fingerlings from a good hatchery. Poor fingerlings are the biggest single cause of loss here: in both documented cases thousands of fish died from them.Supplier
• A small space is enough - a roof, a yard or a patch beside the house, which is the whole attraction of the method. But it has to be high ground with drainage.Workspace

How the work is done

1. 1Find out first how many people in your upazila are doing biofloc and how many have stopped. The district fisheries office recorded 30 in Thakurgaon Sadar, one in Ranishankail and one in Pirganj. One conversation with somebody who shut down teaches more than ten YouTube videos.
2. 2Go to the upazila or district fisheries office and ask about training. The Thakurgaon district fisheries officer says several of his officers have been trained in biofloc and that training can be arranged for interested farmers who get in touch.
3. 3Buy the equipment yourself and do not leave it to anyone else. The successful growers say young people were talked into buying things at inflated prices and over-investing at the start, and could not carry it afterwards. Tarpaulin, oxygen machines and nano tubes are all sold at widely different prices.
4. 4Buy the generator or battery before the tanks go in. When the power fails the oxygen stops and the fish die quickly. This is not an optional extra; it is the core equipment.
5. 5Build in drainage and put the tanks on high ground. One Thakurgaon farmer lost much of his stock in a sudden flood because there was no drainage.
6. 6Get fingerlings from a good source; it is the single biggest decision. Raihan Hossain puts it plainly: good fingerlings from a good place put an operator a step ahead. Poor fingerlings cost both of the failed growers heavily.
7. 7Bring the water's pH under control and add some TDS before stocking, then raise the TDS gradually. That is Shahed Hossain's method, and skipping this step cannot be fixed later.
8. 8Keep oxygen between 6 and 10 and water temperature between 25 and 30, and measure both every day. Feed three times a day at the start and twice a day once the fish have grown.
9. 9Learn to manage ammonia and the bacterial colony. The district fisheries officer says people drop out exactly when they cannot keep oxygen, ammonia and the useful bacteria under control.
10. 10Start with one tank, not two. Abdur Rahman started with two and spent about Tk 4 lakh; learning on one and expanding later would have halved the loss.
11. 11Check the market rate before choosing the species. One Thakurgaon farmer lost on tilapia because the fingerlings were poor and the fish price was low - and one of those two reasons was simply the market.

Sources

• সিটি কর্পোরেশন থেকে ট্রেড লাইসেন্স প্রাপ্তির ধাপ সমূহ

  Collected: 16 Sept 2026

  Supports: Starting capital · বাংলাদেশ

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