NT Labs Formaldehyde

NT Labs Formaldehyde are an excellent anti-parasite treatment, particularly when mixed with Malachite.

Formaldehyde is effective against protozoan parasites and flukes. It is especially useful in treating flukes because of it's ability to penetrate mucus and reach the parasites that would otherwise be protected from other bath treatments.


Two researchers called Leteux and Meyer were the first to publish the fact that the anti-parasitic activity of Malachite green could be enhanced through using it in conjunction with Formaldehyde.

When parasite infections such as Ichthyopthirius white spot, Trichodina, Costia, Chilodonella, and Epistylis are suspected the best treatment is a mixture of Malachite Green and Formaldehyde.

Add 10 ml of Malachite Green, to every 352 gallons (1600 litres) of pond water and 10 ml Formaldehyde to every 150 gallons (681 litres).

A pre-prepared mixture of Formaldehyde and Malachite Green called FMG Mixture is also available in the Koi Care range.

This is a strong one shot treatment, and is thus not suitable for use with those systems that contain sensitive species such as orfe, sterlet, rudd or tench.

Some external parasites such as the flukes Gyrodactylus and Dactylogyrus are best controlled using Formaldehyde alone.

When these parasites are suspected apply Formaldehyde at 10ml per 150 gallons (681 litres) of pond water.

Caution:  Formaldehyde is a hazardous chemical and should be handled with great care, please read the warnings on the label carefully. 250 ml treats 17,048 litres (3750 gallons). The 2.5 litre bottle will give up to seven treatments of 25,000 litres at a time. So the 2.5 litres gives you 10 times the treatment but at less than six times the price.

At a glance:

• 7 Day Application for persistent parasite infections
• Highly concentrated
• Treats white spot, costia, trichodina
• Can be mixed with Malachite
• Can be used on its own against flukes