Evolution Aqua Med Formaldehyde


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EA Med Formaldehyde

EA Med Formaldehyde Anti-parasite treatment for Koi is a powerful, active medication that works to treat parasite diseases such as White Spot, Costia, Chilodonella and Trichodina in Koi Carp.

Common symptoms

Source of formaldehyde when Koi appear to be flicking abnormaly, white spots are visible, Koi are gasping at the surface or mucus appears on their body. Effects of formaldehyde treatment should see a reduction of flashing and an increase in appetite.

koi disease

Dosage Calculations

20ml dose per 2600 litres (572 gallons)
500ml treats 2 x 16,250 litres (3,575 gallons)
1 litre treats 4 x 16,250 litres (3,575 gallons)

In the event of over dosing a treatment carry out large water changes immediately, remember to use dechlorinator.   Carbon can also be used to remove treatments from the water.

Dosage Instructions

1. Calculate the pond’s volume using the following calculation: Length in metres x width in metres x average depth in metres x 1000 = Litres, divide by 4.54 for gallons. (Click here for a pond volume calculator)

2. Shake bottle well.

3. Switch off UV bulbs until 7 days after the last dose. Remove all activated carbon and zeolite from filters.

4. Using the dosing cap provided, add 1 x 20ml dose per 2600 litres (572 gals) of pond water. Add the medication to a bucket of pond water and then distribute this evenly over the ponds surface.

5. This is a two-dose treatment, the pond should be treated again three days later at roughly the same time. For best results, dose with EA Malachite Green or for ease of use, dose with EA FMG Mix instead.

6. If necessary, it is safe to repeat the course of treatment 7 days after the last dose is finished, following a 20% water change.

7. Check all water quality parameters as poor water quality is often a cause of illness.

NOTE: Do not dose during stormy or humid weather. Always aerate the pond well throughout treatment.

Allow time to observe fish after dosing in case of the unlikely event of an adverse reaction. For use only with Koi Carp. Always wear protective gloves when handling chemicals. Do not use if water temperature is above 25°C.

Questions regarding Evolution Aqua Med Formaldehyde

Why do you need to dose twice?

Dosing is kinder on fish – 2 step dosing acclimates fish for higher active dose rate. Dose on day 1 and again on day 4. Some parts of illness lifecycles cannot be killed so active ingredients need to be high for a longer period to attack these parts when the vulnerable part comes around. White spot is a great example of this.

 How long do I need to wait before I can treat again?

You can repeat the dose, or treat the pond with an alternative treatment 7 days after the last dose has finished, following a 20% water change.

Do I need to switch of my UV?

Yes, the UV will weaken the strength of the treatment and make it less effective

Are eaMedications safe to use with Sturgeon, Tench or Orfe?


Should I add extra aeration?

Yes, always aerate the pond or treatment bath during use.

Can I mix medications?

Only Formaldehyde and Malachite Green can be used together, wait 7 days after the final dose, and do a 20% water change before re-dosing, or treating with an alternative medication. Alternatively you could use Evolution Aqua FMG

Additional information


EA Med Formaldahide 500ml, EA Med Formaldahide 1000ml

Delivery Information

All in stock orders placed before 12pm will be shipped the same day unless otherwise stated. Your order will be shipped via the delivery method selected at checkout.

All deliveries (excluding pallets and livestock deliveries) over £50.00 will be sent via 1-2 day courier free of charge. Orders under £50.00 will have both a 2-3 day service available at £3.95 and a 1-2 day service at £5.95 offered.

Please note that all services rely on third-party couriers to deliver on time and in good order. We will alway enever to use the best service available. At the moment this is Royal Mail, UPS and DSL. We will of course do our best to ensure that your delivery arrives when stated at the time of purchase, however, we can not be held liable for delays caused by the delivery company.

Aquarium & Pond Services