Kordon Malachite Fish Disease Control, 4 fl oz

Kordon Malachite Fish Disease Control is a 4 fl oz malachite green medication for aquarium fish. Kordon says it is effective for the control of various external parasites of freshwater and marine fishes, and also effective against common external fungal infections of fishes and eggs.

Quick facts

• Species: Fish (freshwater and marine)
• Size or dimensions: 4 fl oz
• Material or key ingredient: Malachite green (chloride salt)

Why owners like it

• When used as directed, Kordon says the medication will control or prevent common protozoan parasites, including freshwater Ich and marine Ich (Cryptocaryon).
• The brand also says it is effective against common external fungal infections of fishes and eggs, which include Achlya and Saprolegnia.
• Kordon says an extensive body of literature supports its use as an effective agent in the control of fungus on fish eggs.
• The brand notes it utilizes the less common but also less toxic chloride salt of malachite green.
• Kordon says a 4 ounce bottle treats 240 gallons.

Kordon cautions that malachite green can interfere with biological filtration at dosages above 0.10 ppm, and that it is toxic to some kinds of scaleless fishes, including catfishes, loaches and small characins (tetras). The brand adds that care should be taken with sensitive fishes: dwarf cichlids, gouramis, livebearers and barbs. Kordon also says malachite green can permanently color the silicone sealant in aquariums.

If stress develops, Kordon says to remove fish to another untreated aquarium, or to make an immediate partial or complete water change and replace carbon filtration.

Questions owners ask

What is it used for? Kordon says it is an effective medication used for the control of various external parasites of freshwater and marine fishes. The brand also says it is effective against common external fungal infections of fishes and eggs, which include Achlya and Saprolegnia.

Are there cautions to know about? Kordon cautions that malachite green is toxic to some kinds of scaleless fishes, including catfishes, loaches and small characins (tetras), and that care should be taken with sensitive fishes. If you are unsure about your fish, check with your vet.

How many gallons does one bottle treat? Kordon says a 4 ounce bottle treats 240 gallons.