As fish farming has expanded in Bangladesh, one complaint has grown with it: farmed fish carries a muddy or musty smell. Fish bought fresh from the market still gives off the odour when it is cleaned and cooked, and washing it with lemon, salt, turmeric or ginger and garlic does not remove it completely.

Researchers blame two organic compounds that accumulate in the fat of the fish and in the red muscle under its skin — which is why repeated washing or cooking does not clear the smell.

Professor Muhammad Mahfujul Haque of the aquaculture department at Bangladesh Agricultural University traces the source to bacteria. "When closed water is not cleaned for a long time, actinobacteria, myxobacteria and cyanobacteria develop. Two kinds of compound are released from these bacteria — organic compounds called geosmin and 2-methylisoborneol," he told BBC Bangla.

Researchers identify three main reasons those bacteria multiply: overfeeding in the pond, stocking fish too densely for the size of the pond, and not changing the water. In other words, the standard rules of pond aquaculture — density, feed volume and water exchange — are not being followed.

Professor Haque also explained where the odour settles. "It builds up where the fat sits in the body of the fish, or in the upper skin of the fish where the red muscle is, and that is where the bad smell is created," he said.

This is not a small matter, because the sector is large. According to the United Nations Food and Agriculture Organization's report The State of World Fisheries and Aquaculture 2026, Bangladesh ranks fifth in the world in the production of fish and other aquatic animals, and second in catch from inland waters.

Department of Fisheries data put the sector's contribution to national GDP at more than 2.5 percent, and exports are rising alongside production. In such a market, a lingering complaint about taste and smell ends up costing the farmer at the point of sale.

Source: BBC Bangla