NT Labs OctozinNT Labs Aquarium Octozin Treatment is for treating tropical or cold water fish with hole in the head disease and Bloat. These are caused by certain species of bacteria, mostly in cichlids. Use when fish show symptoms of holes, pits, lesions, abdominal bloating, protruding scales, white trailing faeces and loss of appetite. Bloat is most common in African cichlids. Available in 250ml bottles, treating up to 283 litres over a 3 day course.