King British Original Formula WS3 White Spot Control is a veterinary medicine for the treatment of fish infected with White Spot. Also known as Ich or Ichthyopthirius, this is a persistent protozoan parasite that exhibits itself as pinhead-sized white spots.Costia & Trichodina can also be controlled with this product. Suitable for both coldwater & tropical aquariums. WS3 is our strongest strength formulation against white spot - One 50ml bottle will treat up to 4,500 litres of tank water. Active Ingredients: Malachite green (4% solution) 10.0% w/w, Acriflavine 0.05% w/w, and Quinine sulphate 0.04% w/w. Available in a 50ml bottle.