Malachite Green is an effective medication used for the control of various external parasites of freshwater and marine fishes. When used as directed the medication will control or prevent the following common protozoan parasites: Ichthyophthinus (freshwater Ich), Costra, Chilodonella, Ambiphyra, Cryptocaryon (marine Ich), Epistylis, Oodinium and Trichodina. Kordon's Malachite Green is also effective against common external fungal infections of fishes and eggs which include Achlya and Saprolegnia. An extensive body of literature supports its use as an effective agent in the control of fungus on fish eggs

CLINICAL SIGNS
Increased respiration; loss of normal body color; presence of discrete white spots (freshwater or marine Ich); white areas on the body with circumscribed red perimeter [Epistylis]; scratching on tank bottom or on objects; lethargic behavior; white tufts or strands on body [Fungus]; dust like "peppered" spots on body surface, having a yellowish cast [Oodinium].

Malachite Green is not indicated for the treatment of bacterial diseases with the exception of columnaris disease (Hexibacter columnaris), which has been demonstrated to show sensitivity to the drug. The drug is not recommended for use with fry and "scaleless" fishes (see Toxicity). This drug is primarily intended for the control of external parasites and fungi in freshwater and marine fishes. it is a drug of choice for common Ich (Ichthyophthirius).