STERAZIN is used or the control of gill and body parasites which cause fish to flick when no symptoms are visible to the unaided eye. STERAZIN will also aid the control of internal parasites such as Round Worm, Thread Worm, and Intestinal Worm. In order to destroy the parasites in all stages of their life cycle you will need to use the product on days 1, 3, 6, 8 and 10. STERAZIN may also be used to aid the sterilisation of aquatic plants and is highly biodegradable. Do not use when crustaceans, echinoderms, rays, seawater sharks, piranha, sturgeon or sterlets and related species are present. In these instances use Waterlife PARAGON. Suitable for seawater, tropical freshwater and coldwater aquaria. Available pack size and dosage guide Pack Size Treats Waterlife Sterazin 100ml 5 day course treats up to 200 litres Waterlife Sterazin 250ml 5 day course treats up to 500 litres Waterlife Sterazin 500ml (professional) 5 day course treats up to 3000 litres