• Question: Why does fish smell so strongly?

    Asked by Ciara :) to Min, Marcello, Katie, Israel, Dheeraj, Aoife on 18 Nov 2019.
    • Photo: Min Yap

      Min Yap answered on 18 Nov 2019:

      The strong fish smell caused by trimethylamine (TMA), which is a result of bacteria and fish enzymes converting trimethylamine oxide (TMAO) to trimethylamine (TMA), which happens once a fish is killed and out of water for period of time. The strong fishy smell is often used as an indicator of how fresh a fish is. The smell can be reduced either by rinsing with tap water or treating fish with acidic ingredients like lemon or vinegar.

    • Photo: Aoife McHugh

      Aoife McHugh answered on 18 Nov 2019:

      Once fish is killed and removed from the water, microbes on the fish skin break down a compound that is on the surface into two smaller compounds. These are what smell, and the longer the fish is out of the water before it is cooked/frozen, the more smaller compounds produced and the more they smell.

    • Photo: Dheeraj Rathore

      Dheeraj Rathore answered on 20 Nov 2019:

      Fish tissue contain an odorless chemical known as trimethylamine oxide. When the fish is killed, the fish’s tissues are exposed to air, the bacteria in the fish’s body break down this chemical into two new chemicals that are derivatives of ammonia, and therefore fish smell pretty strongly.

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