Mouse anti-Virus HRH4 monoclonal antibody for cI-ELISA. Malachite green is an organic compound that is used as a dyestuff and has emerged as a controversial agent in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper. Although called malachite green, the compound is not related to the mineral malachite - the name just comes from the similarity of color.