Goldfish can survive without food for a considerable amount of time, typically ranging from a few days to a couple of weeks, depending on several factors. In general, a well-fed goldfish can go without food for about 1 to 2 weeks without experiencing severe health issues. However, the actual duration can vary based on factors such as the fish's age, health, water temperature, and overall living conditions.
In cooler water, goldfish's metabolism slows down, which can extend the period they can go without food. Conversely, in warmer water, their metabolism speeds up, and they may require more frequent feeding. It's also important to note that while goldfish can survive without food for this period, extended fasting can lead to weakened immune systems and other health problems over time.
It's crucial to provide a balanced diet that meets their nutritional needs when they are being fed. If you know you'll be away for an extended period, consider using automatic feeders or asking someone to feed your goldfish in your absence. In summary, while they can survive without food for a while, it's always best to care for them properly to ensure their health and longevity.