NT Labs
Diagnosis Tool Dosage Calculator Stockist Finder


From £10.99

Malachite Bulk

Anti-Fungal Treatment for Koi  

Treats: Fungus caused by Saprolegnia

When to Use:

  • Use when fish show white growths on the body, head or fins which may contain some greenish or brownish discoloration.


  • Switch off UV until all the colour has gone from the water.
  • Test your water quality first using Pondlab test kits.
  • Aerate your pond well during medication.
  • Wait 7 days after the final dose before treating with a different medication.
  • If you feel that a repeat dose is necessary, check your diagnosis carefully using the diagnosis tool on our website, a different medication may be more suitable.
  • Always treat when you have time to observe fish and take appropriate action if they react badly.


  • Use at water temperatures above 30oC.
  • Use in hot, humid weather.
  • Mix medications.

View our medicinal treatment rules


Available in the following variations:

250ml, 500ml, 1 Litre & 2.5 Litre

Stockist Finder

Simplified map of the United Kingdom.

Find your nearest NT Labs Authorised Retailer.


Let us calculate your dosage for you!

To make the process of using our products even easier this handy dosage calculator tells you the amount you will need to put into your system. Please ensure you also read the instructions and warnings that are written on the bottle/pack label.

I know my system's measurements and want to:

Calculate my volume
Dosage calculator

Calculate dosage

You’ll require*
0 ml

* Always follow the instructions on the label. This calculator is intended to be used only as a guide to how much product you need to buy to treat your system. It does not take account of displacement caused by gravel, rocks and ornaments etc and does not include the volume of any external filtration system. NT Laboratories Ltd. will not accept any responsibility for inaccuracies or misuse of this guide.