General Rule of Thumb:
* For every inch of goldfish, you should have 1 gallon of water.
Examples:
* Small goldfish (under 2 inches): A 10-gallon tank is sufficient for 2-3 small goldfish.
* Medium goldfish (2-4 inches): A 20-gallon tank is ideal for 1-2 medium goldfish.
* Large goldfish (over 4 inches): A 50-gallon tank or larger is needed for 1 large goldfish.
Important Considerations:
* Overstocking: Never overcrowd your tank. Overstocking leads to poor water quality and health problems for your fish.
* Filtering: A powerful filter is crucial to maintain water quality. Choose a filter appropriate for the size of your tank and goldfish.
* Water Changes: Regular water changes are essential. Aim for 25% of the tank volume every week.
Remember, these are general guidelines. It's always best to consult with a knowledgeable fish expert or veterinarian for specific advice based on your individual goldfish's needs.