Shake Well. To start new aquariums, add entire bottle to aquariums up to 100 gallons. Aquarium is then ready for fish. Consult your retailer for advice on type and number of fish appropriate for your aquarium. For healthy maintenance, add one teaspoon (5ml) for every 10 gallons when adding fish, after water changes or after replacing filter media. Tank Preparation: Condition tap water with Tetra AquaSafe. Maintain a constant, appropriate water temperature in your aquarium.