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how long can fish go without food

How Long Can Fish Survive Without Food?

Are you planning a weekend away? Do you accidentally forget to feed your fish from time to time? Whatever your reasons we are glad you’re here because the survival of your pet aquarium fish depends on your ability to feed them. 

Knowing how long your pet fish are likely to survive without food will make you a better fish owner. Sure, they may not be happy with you when you forget to feed them.

But, at least you’ll know that they have got it in them to patiently wait. You’ll be back, right? In this article, we will present everything there is to know about fish surviving without food.

When the fish food container empties and the aquarium floor scraps are scarce at best, how long have you really got? Let’s find out. 

How Long Can Fish Survive Without Food?

Obviously, there is no blanket rule across all fish species on their chance of survival without food. They differ in size and biology far too much for such a broad spectrum answer.

However, with the help of examples and averages, you will have a better understanding of your aquarium fish and their need for food. 

how long can fish go without food
Dinner time!

How Long Can Fish Survive Without Food In The Wild?

As its namesake gives away, the wild is a wild place. Fish in the wild are hardened individuals who are used to skipping meals for days of no end (no they aren’t dieting).

Having to catch prey on their own accord means eating regular meals is a luxury that wild fish can rarely afford.

Occasionally, there is an overabundance of their food source and they will feed to the point where swimming becomes arduous. These are the glory times for wild fish.

As a result of the sporadic chances of them feeding, fish in the wild have evolved to sustain long spells without food. For example, female African Cichlids can last one month without food when mouth-brooding.

Even though this is one of the more impressive examples, most wild fish species are well accustomed to surviving without food for at least one week and sometimes two. 

How Long Can Fish Survive Without Food In Your Aquarium? 

Even aquarium fish are capable of surviving multiple days without a trace of food to gobble down. On the lower end, small aquarium fish can last three days without food. Larger aquarium fish like Oscars can last for up to one week without food.

This is quite impressive when you consider that their entire life has been spent inside an aquarium. They are also conditioned to eat one square meal a day (unlike wild fish).

So, even though most aquarium fish would almost certainly not be able to cut it in the wild, their biology still gifts them the ability to survive for days without food. Maybe they aren’t such softies after all. 

How Can Aquarium Fish Survive Long Periods Without Food?

how long can fish survive without food
Colour co-ordinated lunch.

It makes sense why wild fish can survive long periods without food, it’s all in a day’s work for them. Still, the question remains, how are aquarium fish so good at it having spent their entire lives living the easy life in captivity?

The simple answer is that they have adequate body mass and fat reserves to be able to sustain periods of no food. Quite impressively their bodies haven’t de-evolved because of captivity.

Of course, the same can’t be said for their hunting skills and tenacity to fend off and escape from large prey. But, hey, we’re discussing food, not tenacity. 

In fact, many fish experts believe that humans actually overfeed their pet fish. Overfeeding is known to slow fish down and make them especially lazy. So, just like we need to watch what we eat, your pet fish skipping the odd meal isn’t such a bad thing after all. 

How Will Your Pet Fish Fry Last Without Food?

So now you know that at least your adult fish will do okay on your planned weekend away, but what about the fish fry? Whether you are buying baby fish from the aquarium shop or your friskier fish ended up making babies, regular feeding is key to their survival. 

Just as human babies require feeding every few hours, fish fry have similarly needy eating habits. In general, you should expect to feed your fish fry at least three times a day when they are new to the world.

This can be a tricky task in an aquarium filled with large fish looking for a quick and easy feed. Any fish that isn’t the parent of your fish fry will see them as adversaries who, one day, they will have to contend with for food.

This is why growing fish fry in a separate tank is a clever idea. This will gift them the best chance of regular feeding and survival.

What Are Some Tips For Feeding Fish While Your Away?

Pouring an entire fish food container into your aquarium before running out the door on a weeklong holiday and hoping for the best maybe isn’t such a good idea.

There are more responsible ways of mitigating fish food when away from the home. The best way of feeding fish while away is getting a neighbor, friend, or family member to stop by every couple of days to feed the fish.

If this isn’t a possibility for you, then there is still hope. There are specialist fish feeding tools out there that can be fixed above aquariums.

These fish-feeding machines can be set to daily timers and dispel pre-determined amounts of food. This should keep your fish happily swimming until you get home. 

This automatic feeder is only for fish tanks that don’t have a lid.

This feeder works in a tank with a lid as it can be attached to the side of the tank with suction pads.


So there you have it. You’re now all the wiser about your fish’s ability to survive without food. We hope this article has been a useful tool in learning how to keep your fish alive when the beach is calling and no one is around to feed your fishies for the weekend.

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