1. The pH of the water is 9 or above, malachite green should not be used.
2. Malachite green is considered a carcinagen.
3. For food fish, malachite green is not approved to use.
4. Some species and life stages if fish are highly sensitive to malachite green and this chemical should not be used with these fish, such as very young fish, bass and bluegills.
5. Gloves should be worn when using malachite green
malachite green has not been approved by the Food and Drug Administration (FDA) for use with tilapia. Thus, it is not currently legal to use this substance to treat tilapia especially if these fish or their offspring are intended for human consumption.
malachite green may be legally used only if there is a current Investigational New Animal Drug Application (INADA) in effect for treatment of the particular disease at the particular site. It is the responsibility of the user to know if an INADA is in effect for malachite green for use with tilapia on his or her site. The user must be familiar with and to comply with the conditions for an INADA for malachite green.
Malachite green is a dye that has been long used as a treatment for external infections by fungi and some protozoan ectoparasites of fish. Malachite green crystals dissolve in fresh and salt water and are considered as 100% active.
For the treatment of fungus infection, malachite green has been used as a short duration dip (67 ppm for 15-30 sec.). At the dip dosage exposure duration should not exceed this recommended level. Malachite green has also been used as an indefinite bath for the treatment of external protozoan parasites, fungus and bacterial infections. Dosage is 0.1 ppm.
Some species (ie. blue gills and bass) and/or very young fish (all species) are considered to be highly sensitive to malachite green toxicosis. Young fry tilapia should not be exposed to malachite green.
Malachite green is considered to be a potential carcinogen. Thus, if used, avoid any direct contact with malachite green crystals or concentrated malachite green solution. The FDC has not approved malachite green for use in food fish species.
Also used with Formalin