Here are some tips for providing goldfish with good quality water:
- Use a filter to remove impurities from the water.
- Change the water regularly (at least once a week for a small tank, and more often for a larger tank).
- Test the water regularly to make sure the pH and hardness are within the ideal range for goldfish.
- Add plants to the tank to help oxygenate the water and provide hiding places for the goldfish.
- Do not overcrowd the tank. Too many goldfish in a small space can lead to poor water quality and health problems for the fish.