Fish Zole is a water-soluble antibiotic used to control gram-positive and some gram-negative bacteria in fish. It is useful in controlling of some common fish diseases including Aeromonas, Pseudomonas genera and Mycobacterial Group (Gill disease, Chondrococcus). It is also used to control diseases caused by parasites such as Cryptocaryon irritans, Hexamita, Ichthyophthirius multifiliis. Each tablet of Fish Zole contains 250 mg Metronidazole. Each tablet or packet of Fish Zole Forte contains 500 mg Metronidazole.