Fungicides are chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality and profit. Fungicides are used to treat fungal infections in animals.
Malachite green (MG), also called Basic Green 4 or Victoria Green B, is a toxic chemical primarily used as a dye in the leather and paper industry. When diluted, MG has been used around the world extensively for the treatment of external fungal and parasitic infections on fish eggs, fish and shellfish and is an effective fungicide, especially as a general hatchery disinfectant.
MG and its reduced form, leucomalachite green (LMG), may persist in edible fish tissues for extended periods of time. MG can cause significant health risk for humans who eat contaminated fish. For example, it can cause liver tumor formation and is suspected of carcinogenesis.
The EU, US, Japan, China and many other countries have banned MG in aquaculture. For this reason,within the EU a minimum required performance limit (MRPL) has been established for the sum of MG and LMG (Commission Decision 2002/657/EC).