Abdul Momin, a resident of Rajarhat union in Kurigram, has succeeded in applying biofloc technology to raise native breeds of fish in his very own backyard.

Biofloc technology is a fish farming system that recycles waste nutrients as fish food, helping maintain water quality while also lowering costs.

Having learned this technique from a YouTube tutorial, Momin dug two reservoirs of about four feet deep on his own property as he lacked the required capital for leasing land due to previous losses.

Momin, who is a madrasa teacher by profession, then released 57,000 koi and 3,000 tengra fish fry into the reservoirs on August 19 last year.

All in all, he spent almost Tk 2.1 lakh for constructing the enclosures and purchasing the necessary materials, including air pumps, feed and medicine.

Momin has since regained his investment, registering sales of Tk 3 lakh by the first week of January.

Having started selling the fish on December 20, he went on to sell another Tk 2.5 lakh worth of fish by the end of last month.

"Farming fish in this manner requires regular maintenance and vigilance, but we can produce more fish at a lower cost in less space by following this method," Momin said.

Seeing his success, other farmers in the locality are now interested in applying biofloc technology.

"This year, I will start farming fish on a small scale in my backyard using this method," said Abu Taleb, a local farmer who learned about biofloc technology from Momin.

Subhash Chandra Das, a fish trader, said he buys fish from Momin for Tk 200 per kilogramme and sells it for up to Tk 280 in local markets.

Momin said he gives all kinds of support to people who approach him to learn about biofloc fish farming.

And while this method may seem costlier at first, the money saved on cleaning the reservoir and feeding the fish almost doubles the profit, he added.

Momin then said that the method can be applied year-round, sans two months during monsoon season.

Kalipada Roy, the district fisheries officer of Kurigram, said they too will provide any assistance required to those interested in biofloc farming.

"I hope some 25 to 30 farmers in the district will start using the method this year," he added.

Manirul Islam, deputy director of the Department of Fisheries in Rangpur, said biofloc technology ensures good profits from relatively small investments.

However, this method is yet to gain the proper traction as only five or six people are using it.

"As we haven't received any instructions from the government to encourage fish farming in this method, no pilot project has been taken up yet. But if anyone is interested, we give advice,'' Islam added.

About 46.21 lakh tonnes of fish were produced in Bangladesh in fiscal 2020-21, which was more than twice the amount registered about two decades ago thanks to the expansion of aquaculture.

At present, cultured fish accounts for 57 per cent of the annual production while it was 41 per cent in fiscal 2001-02.