How Long Can Fish Go Without Food?

Like animals, fish differ when it comes to their nutrition styles and eating habits. Some eat more, others eat less, some eat meat, and others eat plants.

Even though it is the best to have fish eat an appropriate amount of food daily, we sometimes are unable to. We might be going on a vacation, have a work trip, or are away from home because of something else. This is why it is so important to know how long your fish can go without food.

Understanding your fish

To crack this mystery about your fish, you have to get to know them better and be aware of the factors that shape their feeding styles.

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Fish can be carnivores, herbivores, limnivores, or omnivores. Carnivorous fish have a diet that is based on meat. Puffer fish, cichlids, and arowana are all carnivorous fish that people tend to keep in aquariums.  

Herbivorous fish, on the other hand, like eating plant-based food. The brown tang is an herbivorous fish that can be found in some people’s aquariums. Also, mollies and silver dollars are primarily herbivorous fish that many people keep as pets.

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Fish that are omnivores eat both plants and meat. The catfish is one of the most famous fish that people keep in aquariums.

Limnivores fish feed on foods that are mud-based, and they also eat algae and microorganisms.

Out of all these fish, it is the herbivores and lemnivores that need to be fed more often. They cannot go long without food because the nutritional value of plants is low, and these fish need to feed more often in order to survive. Omnivores and carnivores, on the other hand, can survive without food longer. That’s because meat is very caloric, and fish that eat it will have more energy to store.

What also determines how much time your fish will be alive with nothing to eat is its age. Younger fish need more food because they are still growing and require more energy. Older fish, however, have a lot of fat in their bodies, and that fat can be burned down in the absence of food.

How to help your fish survive without food

To help your fish stay alive without food, you could turn off the lights in your aquarium. That will decrease the level of their activity and reduce the energy they’ll spend. Furthermore, you could also lower the water temperature for a couple degrees. This will slow down their metabolism and make them digest the food at a slower pace.

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You can also try extending the time period between the meals and observe how the fish will react to the change. This way, you will reduce the effect from the shock that they’ll experience once you leave them without food for a longer time.

Other alternatives

Leaving your fish unfed can be dangerous for their lives. If possible, you should have someone to take care of your fish when you yourself are not able to. Aside from feeding them, this person could watch over the fish and help them if something goes wrong.

Another thing you could do is buy an automatic fish feeder. There is a variety of different models and types on Amazon. The feeder will release a decent amount of food in the tank at specific time intervals. Automatic fish feeders are very flexible, and you could also control the amount of food per portion that your fish can eat.

There are also degradable cubes that your fish can feast on while you are not around. However, they will not last long in the water.


We strongly recommend you buy an automatic fish feeder before you leave your fish alone. Even if you are to be away for a few days only, you should try to find a way to keep your fish fed. However, if you have to leave your fish with no food for few days, the information in this article might be useful to you.