What causes fishy smell?

As fish is left to stand, bacteria convert a compound called TMAO in the flesh of sea fish into trimethylamine. What we call a fishy smell comes largely from this substance.

Why does frying smell last for days?

As oil vapour cools, it settles on the curtains, the cooker hood filter and cupboard doors. Opening the window clears the smell from the air, but the thin film of oil on surfaces keeps on smelling.

How do you use Air Biotics in the kitchen?

Once you've finished cooking, spray 3-5 times into the room air, and onto the curtains from 20-30 cm away.

Kitchen · 4 min read · 3 October 2026

Why won't fish and frying smells go away?

Trimethylamine, oxidised oil and vapour settling on curtains. The chemistry of the smell that spreads from the kitchen to the living room.

(CH₃)₃NTrimethylamine

In short

1The main source of fishy smell is trimethylamine, which bacteria produce from the TMAO in fish.
2When frying, heated oil oxidises and forms odorous compounds.
3Both settle with the oil vapour on curtains, cupboards and worktops; that's why the smell can last for days.

Why does fish smell fishy?

The flesh of sea fish contains a compound called trimethylamine N-oxide (TMAO). In fresh fish, its smell isn't noticeable. As the fish is left to stand, bacteria convert TMAO into trimethylamine, and what we call a 'fishy smell' comes largely from this substance.

The smell isn't in the air, it's on surfaces

When you fry food or cook fish, oil vapour gets into the air. As the vapour cools, it settles on the curtains, the cooker hood filter, cupboard doors and even the living room sofa. Opening the window clears the smell from the air, but the thin film of oil on surfaces keeps on smelling.

While cooking and afterwards

Limiting how far the smell spreads is easier than trying to get rid of it afterwards.

01Switch on the cooker hood before you start cooking and run it for another 10-15 minutes after you finish.
02Keep the kitchen door closed.
03Wash the cooker hood filter regularly; a greasy filter carries the smell itself.
04Once you've finished cooking, apply a probiotic spray to the air and the curtains.

Questions

What causes fishy smell?: As fish is left to stand, bacteria convert a compound called TMAO in the flesh of sea fish into trimethylamine. What we call a fishy smell comes largely from this substance.
Why does frying smell last for days?: As oil vapour cools, it settles on the curtains, the cooker hood filter and cupboard doors. Opening the window clears the smell from the air, but the thin film of oil on surfaces keeps on smelling.
How do you use Air Biotics in the kitchen?: Once you've finished cooking, spray 3-5 times into the room air, and onto the curtains from 20-30 cm away.

Sources

All literature →

01
Fish spoilage bacteria – problems and solutions
Gram L, Dalgaard P (2002). Current Opinion in Biotechnology 13(3): 262-266
doi:10.1016/S0958-1669(02)00309-9
Finding · ReviewTrimethylamine-N-oxide (TMAO), found in the flesh of sea fish, is reduced to trimethylamine (TMA) by spoilage bacteria. The typical smell of spoiled fish comes largely from TMA.

These studies were not carried out with Air Biotics. What we say about the product is limited to what is written on its packaging; Air Biotics is not a disinfectant.

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