Betta fish can survive for about a week without food.
The survival time of betta fish mainly depends on water quality and environmental conditions. Under ideal conditions, such as clear water without impurities, betta fish can survive for about a week. If the water quality is good and there are aquatic plants, etc., the survival time of betta fish can be extended to about a month. This is because betta fish can rely on microorganisms and algae in the water to a certain extent to maintain their lives. At the same time, they may also eat other small fish in the fish tank to extend their survival time. However, not feeding for a long time is very unfavorable to the health of betta fish, which may lead to malnutrition and a decline in physical condition, and even cause death in severe cases.
In addition, as a carnivorous freshwater fish, betta fish need to continuously take in nutrients to maintain normal physiological functions and a healthy state. Under normal circumstances, betta fish can go without eating for three days, but not feeding for a long time is very harmful to their health. The diet of betta fish raised at home should be regular, and the amount of food fed every day should be controlled at about 1% to 2% of the size of the betta fish's belly to maintain their health.
To sum up, the time that betta fish can survive without food depends on water quality, environmental conditions, and whether there are other food sources. For the health of betta fish, it is recommended to feed regularly and avoid not feeding for a long time.