Dennerle Black Cones/Alder Cones with valuable humic and tanning substances which protect and benefit aquarium fish by natural means. - For aquarium water similar to the natural tropical aquatic habitat. - Promote well-being vitality and spawning instincts. - Prevent fungal diseases and spawn mould in fish. - Have a slight acidifying effect and stabilise the pH value. - Ideal for fish from black water regions such as discus neons scalares dwarf cichlids long-whiskered catfish etc. 50 alder cones for 1200 litres