• 1
    Regulate the water temperature.Because silver dollar fish tend to naturally inhabit waterways in South America, they typically thrive in slightly warmer water temperatures. Use a water heater and keep a thermometer in or near the tank so you can regulate the temperature as needed.
    • The ideal water temperature range for silver dollar fish is between 75 and 82 degrees Fahrenheit (23.9 to 27.8 degrees Celsius). However, they may be able to survive in temperatures as low as 71.6 degrees Fahrenheit (22 degrees Celsius).
  • 2
    Measure the pH.Percent hydrogen, or pH, is a measure of how acidic or basic a sample of water is. Some breeders recommend maintaining a pH between 6.0 and 7.5. However, silver dollar fish can survive in water with a pH as low as 5.0 and as high as 7.8.
    • Check the pH every time you change the water. You may also want to test the pH of your water source to ensure that you're not introducing acidic or basic water to an otherwise stable environment.
    • You can raise the pH by adding an alkaline buffer and lower it by adding an acid buffer. Both products can be purchased at most pet stores or through an online retailer.
  • 3
    Measure the pH.Percent hydrogen, or pH, is a measure of how acidic or basic a sample of water is. Some breeders recommend maintaining a pH between 6.0 and 7.5. However, silver dollar fish can survive in water with a pH as low as 5.0 and as high as 7.8.
    • Check the pH every time you change the water. You may also want to test the pH of your water source to ensure that you're not introducing acidic or basic water to an otherwise stable environment.
    • You can raise the pH by adding an alkaline buffer and lower it by adding an acid buffer. Both products can be purchased at most pet stores or through an online retailer.
  • 4
    Change the water in your tank.You should completely change the water at least once every month to ensure a stable habitat. However, changing the water too frequently can deplete the bacteria your fish rely on. Because of this, it's recommended that fish owners perform partial water changes in which approximately 25% of the water is replaced. Partial changes can be performed about once every two weeks, though tanks that get dirty very quickly may need more frequent partial water changes. You may not be able to use tap water for your aquarium, depending on the mineral and chemical composition of your water. Test your water at home before using it in your aquarium.
    • Unplug any electrical devices, such as your heater and/or an overhead lamp.
    • Scoop out your fish using a hand net and transfer them to a safe bucket or second tank while you clean. Then remove and clean the filter and any artificial plants or decorative accessories you may have submerged in your tank.
    • Use a gravel cleaner to siphon out debris from the bottom of your tank. However, you should not use a gravel cleaner if your fish have recently laid eggs in the aquarium.
    • Reverse osmosis water does not have any impurities, but it also lacks minerals that your fish may need. If possible, use only deionized water for your fish tank.
    • Measure the temperature of your water and adjust the clean water's temperature accordingly before adding it to the aquarium. Then replace the items you removed and scoop your fish back into their primary tank.

Source:wikihow