Healthy water makes for a healthy aquarium. It is best to follow the example set by nature, in which tributaries and rainfall ensure that water always remains fresh and harmful substances are removed by effluent and seepage water. Carrying out regular partial water changes is the most important part of aquarium care, besides feeding. In aquariums with a standard stock of fish and level of plant life, one third of the aquarium water should be removed by suction at least once every two weeks and replaced with temperate tap water. This water can be made safe for fish by using Tetra Goldfish AquaSafe, which neutralises heavy metals and reduces the water’s chlorine content. In addition to this, it also contains valuable organic colloids to provide the best possible protection for delicate fish mucous membranes.