Malachite green
From Freepedia
Malachite green (also aniline green, basic green 4, diamond green B, or victoria green B, IUPAC name:4-[(4-dimethylaminophenyl)-phenyl-methyl]-N,N-dimethyl-aniline) is a toxic chemical primarily designed to be a dye and is subsequently used to treat parasites, fungal infections, and bacterial infections in fish and fish eggs.
Malachite green is used to dye materials like silk, leather, and paper. The chemical known as malachite green does not actually contain the mineral malachite — the name comes from the similarity of color.
Malachite green is also found to be especially active against the fungus Saprolegnia, which infects fish eggs in commercial aquaculture. It is also a very popular treatment against Ich in freshwater aquaria. The principle metabolite, leucomalachite green (LMG), is the main chemical found in fish treated with Malachite green. This is due to its longer retension time inside fish muscle tissues.
The use of this substance has been banned in many countries due to its suspected carcinogenicity effect. This suspicion began after lab tests revealed that rats fed malachite green at the concentration of 100ppb for longer than 2 years showed signs of tumours.
An investigation by the Hong Kong Government Labs revealed fresh water fish, crabs and other aquaculture products in China had small traces of this toxin.
Malachite green is known to be highly toxic to certain freshwater fish such as tetras, catfish and shark catfish. It is strongly recommended that half-dosage be observed in treating freshwater tanks with catfish, tetras, scaleless, and other bottom feeder fish.
Malachite green is used as a biological stain for microscopic analysis of cell and tissue samples. In the Gimenez staining method, basic fuchsin stains bacteria red or magenta, and malachite green is used as a blue-green counterstain. Malachite green can also be used to directly stain spores within cells; here a safranin counterstain is often used.
