Before you place fish into your freshwater aquarium, clean the aquarium, and the area where you will set the tank. You can clean your aquarium with a diluted bleach solution (one teaspoon of bleach for five gallons of water), as long as you thoroughly rinse the aquarium afterwards. Place your aquarium near an electrical outlet and away from direct sunlight.
Install the aquarium’s filtration system (the best filters serve as biological, chemical, and mechanical filters) according to the manufacturer’s instructions and insert aquarium gravel. Then, unless the pet store told you otherwise, add regular tap water to the tank and fill the aquarium to approximately one inch from the top. Next, install the heater, keeping in mind that tropical fish prefer a water temperature in the high seventies, while coldwater fish want the fifties and sixties. Add any other devices you have, such as an air pump, chlorine remover, and then run everything for a day before adding your fish.
Finally, one big part of the fun of having an aquarium is designing an entire aquatic environment through the use of ornaments. In addition to the gravel, look into plants, hideouts, and florescent lamps, all of which add lively color to your aquarium.