BD Treat Anti Ulcer 250ml Treats ulcers bacterial gill disease and dropsy Effective treatment Unique formulation Use when: Ulcer like sores appear on the fishes skin; gills are rotting and reddening of fins and skins. Fish are suffering from emaciation (sunken belly) lethargy (sluggish) or clamped fins. Fish are dying without obvious cause Acts Against: Systemic bacterial infections e.g. ulcers bacterial gill disease dropsy etc. 1 x 25ml measure treats 454 litres - 250ml bottle treats 2273 litres (500 gallons).