It's important to remember that goldfish are active swimmers and produce a lot of waste, so a larger tank will provide them with more space to move around and help to keep the water quality high. Additionally, if you plan to add any other fish or plants to the tank, you'll need to factor in their space requirements as well.
Here are some additional tips for setting up a fish tank for goldfish:
* Use a filter rated for a tank at least twice the size of your actual tank.
* Provide plenty of hiding places, such as plants or decorations.
* Maintain the water temperature between 65-75 degrees Fahrenheit (18-24 degrees Celsius).
* Test the water quality regularly and make water changes as needed.
* Feed the goldfish a high-quality diet and avoid overfeeding.
By following these tips, you can help your goldfish thrive in their new home.