Recipe for Koenike’s fluid

Koenikes fluid is one of the best way to kill, preserve and store dead water mites.

Several different recipes are used.

  • 10% glacial acetic acid, 50% glycerol, 40% water
  • 10% glacial acetic acid, 45% glycerol, 45% water

In Gerecke 2010 i’ve read that the proportion are not very important for a good conservation of the water mites.

In France, the glycerol is easy to obtain in small quantity in pharmacy but it’s a little bit harder to get the glacial acetic acid.

My pharmacist was able to provide me a bottle of one liter of acetic acid in aqueous solution. It is not the glacial form but a 85% to 90% solution. This mean that the 10% glacial acetic acid must be replaced by 12% of acid acetic.


  • You must not began the mixing with the acid. The acid must be added the last. If put first you may have an important exothermis reaction.
  • Wear gloves and protecting glasses during the operation.

Fluids to avoid for the water mites.

  • Ethanol : only eventually for a few days.
  • Formalin : makes the body rigid and difficult to clear.





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