Histopathology of the Liver of Three-Spotted Gourami, Trichogaster Trichopterus, Exposed to Malachite Green, A Commonly Used Medicine in Aquaria

With the intensification of aquaculture and the heightened interest in ornamental fishes and fish keeping, use ofmedicaments has considerably increased. These agents are heavily bio accumulated by fish. In spite of this importanceof drugs/therapeutic agents in fishery science, no serious attempt has been made to assess their effects on fishes,especially the histopathological changes brought about by them. Liver is the chief metabolic and detoxification organin vertebrates and it is highly susceptible to metabolic disturbances and a variety of toxicants to which the animal isexposed. Results of controlled exposure of fishes in the laboratory to toxicants such as pesticides and related chemicalssuggest that liver is the organ in which the highest residues of such toxicants accumulate and it is this organ thatsuffers the greatest damage and impairments following such episodes. The present study was, therefore, aimed atassessing the histopathological effects of therapeutic level of malachite green on the liver of a common aquarium fish,the three spotted (blue) gourami, Trichogaster trichopterus. The drug selected for the present study was malachitegreen, a chemical recommended for treatment of fishes against several infection, especially fungal infection of eggs.Malachite green is used at concentrations of 0.05-0.15 ppm in fish disease therapy. Healthy fishes of about 70.0±5 mmTL purchased from a local aquarist were used for the present study. Fish were exposed to malachite green for a periodof 48 h in all-glass aquarium tanks. The exposure concentration of malachite green was 0.15 ppm. The procedures forhistological studies were basically in accordance with the commonly practiced histological methods.