Zebra danios can go up to 14 days without food. Zebra danios are very hardy and have a higher fasting tolerance compared to other species. A healthy adult danio has sufficient body mass and fat reserves to help them survive without food.
However, you shouldn’t leave your zebra danios starving for two weeks, as this can lead to malnutrition, sickness, and even death. You should feed your zebra danios once or twice a day.
Only feed them what they can finish within three minutes to avoid polluting the water. If you’re worried you might be overfeeding your zebra danios, you can let them fast for one day every week without any problems.