To ensure the well-being of your goldfish and avoid any potential conflicts, it's recommended to keep them in a tank that is spacious enough for all the fish to move comfortably without feeling overcrowded. Additionally, providing them with an adequate amount of food, and feeding them simultaneously, can help minimize any competition for resources and reduce the risk of aggression.
It's also important to remember that goldfish come in different varieties and sizes, and their behavior can vary depending on their specific characteristics. Some goldfish breeds may be more aggressive or territorial than others. Therefore, it's always a good idea to research the specific requirements and behavior of your goldfish to ensure they are compatible before keeping them together in the same tank.