How Long Can Fish Go without Food?

There are many people who love to have pets. Pets are a great companion to an individual. People keep different kinds of pets from dogs to fish and even snakes. With different types of pets come different responsibilities.

Normally there is a saying that, if you have a pet you can’t go outside for any vacation. Here we will be discussing pet fishes. So you have decided to go on a vacation but you have an aquarium with your fish babies to take care of.

Now a very common question that the owners of fishes have is, how long can their fish go without eating? 

There are a variety of answers to that question. It is an estimate that some fishes can go for about 1 to 2 weeks without food. But is it good to leave your fish without food for that long? Will there be any consequences?

Even if there are consequences you cannot take your fish with you, then what can you do to solve this issue? While feeding or not feeding your fish you have to keep a lot of things in your mind to save them and keep them healthy.

How Long Can Fish Go without Food in An Aquarium?

The very first question that we have to figure out is what is a general estimate of days that fishes can go without eating. The answer to this question varies from fishes to fishes. There are a wide range of fishes that can be kept in an aquarium.

Large fish, small fish, herbivores, carnivores etc. And all these affect the time limit a fish can go without eating. It is a general estimate that fishes can go for at least 1 to2 weeks without food. But sometimes this might badly affect the health of the fish.

If we understand the concept, fishes are generally found in the environment where they live under very harsh conditions. Fish underwater don’t get their food on a daily basis.

They have to hunt for their food and then they can find food for a day. Basically fishes that are carnivores tend to eat in internals because of non availability of continuous food.

But this cannot completely prove that fishes in aquariums can also stay without food for long, because fishes in aquariums are being continuously adjusted to an environment. An environment where they are being given proper food at a particular interval.

Now if you suddenly disrupt this cycle for them, it may cause stress and affect their health. Therefore, you can leave your fish for 3 to 4 days without feeding them and they will be completely fine.

But if you are thinking of a long vacation or work then you have to go for different solutions.

What Are Some Examples of Fishes how Long Are They Estimated to Go without Food?

There are a variety of fishes around the world which an aquarium lover can keep. Different fishes have different living and eating habits. Some fishes are tough and some are fragile.

Fish like Betta, Gold fish, Platies, guppies , mollies, Koi fish, Danios, Plecos, Oscars, swordtail fish, Corydora catfish, Barbs, etc. Are some of the freshwater fishes that can be kept in an aquarium and can go without food for an estimate of 10 to 14 days.

Fish like Neon Tetras, Angelfish, RasBoras, African Cichlids, Clown Loach etc. Are also some of the freshwater aquarium fishes and they can go without food for an estimate of 7 to 10 days.

Fish like Firefish and Butterfly fish are some of the Saltwater fishes which can go without food for an estimate of 7 to 14 days. Other Saltwater fishes like, Tang, clownfish and Damselfish can go without food for at least a week and more. 

So as you can see, different varieties of fishes show different eating habits. There are numerous factors that go into the eating habits of these fishes, their metabolism, size, health etc.

So whenever you have to see whether your fish can live without getting food for some days, you will have to do a trial by not feeding them once in a while.

But this method of trial is not advisable because it can disrupt their cycle and cause them stress. So while doing any of it you should be extremely careful about their behaviour and health. 

How to Know Your Fish Is Hungry?

There are different ways to know whether your fish is hungry:-

If They Roam at Random Places in The Aquarium

 If you see your fish roaming at random places in the aquarium where it normally doesn’t, then it can be an indication that your fish is hungry.

Generally hungry fishes swim at the bottom of the fish tank to get any flakes of food or roam at the top of the aquarium whenever they are hungry. So this is a way you can determine whether your fish is hungry or not.

If They Are Not Active

If you have a fish which is generally very active and suddenly they are not active and remain Static then it might indicate that they are hungry. Some fishes slow down when they are hungry.

But in adverse conditions even after your fish is given food if it remains slow and static then it means your fish is sick. But if not then, after giving food you will find your fish happily swimming again.

If They Become Aggressive

If your fishes start aggressively pocking other fishes then it is an indication that your fish is hungry and angry. Some fishes tend to get angry when they don’t get food and start distributing other fishes.

In such a case you should immediately give food to your fishes to stop them from hurting other fishes.

So these are some of the methods which can help you easily determine when your fishes are hungry, but this is not an exclusive method of determination.

Because sometimes the above-mentioned behaviour can also be an indication to many things in a fish. You just have to understand the pattern and deal with your fishes.

What Are the Factors that Affect the Time Your Fish Can Go without Eating?

There are numerous factors that affect the eating habits of your fish and as to how long they can go without food. So while determining whether to leave your fishes unattended for days, you have to look into the following factors:-

Herbivore or Carnivore

The requirement to eat for fishes varies depending on their choice of foods. Fish species which are herbivores like Pleco etc, are the ones that depend on plant based food and they require eating more frequently then the carnivores.

Because also in the wild environment, plants are easily available as food and these fishes have the tendency to eat continuously. On the other hand, if your fish is a carnivore then it can go without food for 2 to 3 days without any problem.

Because carnivore fishes don’t get food at a regular interval and they have to hunt for their food.

Age and Size

Age of the fishes is also an important factor to consider while thinking of not giving food to your fishes. Fish which are young need to be fed 3 to 4 times a day or else they will be sick and at worst die.

But fishes which are of more age don’t need to be fed so often. They can go without food for some time and it would not affect their health.

Size of the fish is also a determining factor. Fishes which are small are more active and they have high metabolism. Whereas fishes that are large have low metabolism with high body mass and fat reserves.

Therefore fishes that are small need more food for their growth and the larger fishes need less food. 

Age of Your Aquarium

Yes, how old or new your aquarium is also important. When you set up a new aquarium you have a completely new environment setup for the fishes.

In such a case the fishes have not adjusted to the environment and their eating habits have also not been set up.

Filtration system of aquarium should also be working properly. Aquarium plants, feeding blocks, aquarium lights are good for fish habitat. 

How to Change the Eating Habits of The Fishes in Your Aquarium?

There are different ways through which you can regulate the eating patterns of your fish. Some fishes eat food twice a day, while some eat 4 times a day, generally baby fishes. Now we can change the eating habits of the fishes by some of the following methods:-

Changing the Timing for Lights

The lights of an aquarium acts as an indication to the fishes for determining day and night. Fishes at night are generally the least active and during the day they are highly active. So you can change the light duration from 12 hours to 7 to 6 hours.

By doing this the daytime will become less for the fishes and duration of the night will increase. This will lower their metabolism and they will eat less. 

Lowering the Temperature

You can also decrease the metabolism of a fish by lowering the temperature of an aquarium. But you should keep in mind not to excessively lower the temperature of your fish tank as that would have a negative effect on your fish.

Fishes in aquariums having lower temperatures need less food and they don’t eat often. So these are some of the steps to decrease the times your fish needs food. But you cannot suddenly change all these in your aquarium environment.

You have to gradually make these changes so that your fishes easily adapt.

How to Feed Your Fish when You Are out On a Vacation?

As you know now , without giving food to your fish you can still go for a weekend and the fish will remain healthy.

But what if you are gone for a very long time, then you cannot just leave your fish without food. In such a case there are different ways by which you can you can feed your fish:-

Automatic Feeder

Automatic fish feeder is one of the latest fish feeding devices that has come to the rescue of aquarium owners. It helps in feeding your fish for 1 to 2 weeks and is battery operated. By this feeder you can easily feed your fish by setting up a timer.

This feeder can feed flakes and all kinds of dry fish food without causing any mess to the water and without overfeeding the fishes.

Automatic feeders are easily available online and will be a great thing to invest in, if you want to enjoy a tension free vacation and your fish will also remain healthy by the time you are back.

Fish Sitters

Another way is to ask someone to look after your fish while you are gone. Relatives, friends or kids that have a bit of knowledge about your fishes and aquarium so that they don’t overfeed your fishes.

Also you can hire professional fish sitters as they can feed your fishes and also look after your aquarium and keep it clean or remove any dead fish.

Vacation Feeders or Food Blocks

These are some pocket friendly food blocks that are available for the fishes. You just have to toss one of the food blocks into your aquarium and it will start releasing food in water.

But the biggest drawback of these blocks are, since they continuously release food into the water they can overfeed the fishes, the fishes might not even like the food released and they might disrupt the aquarium environment.

So before using this you should first try it out in your presence and if it is suitable you can go for it.


Thus the answer to whether your fishes can go without good for someday, is yes. Fishes can sustain without food for 3 to 4 days without food easily.

But the risk of not feeding them still remains. Therefore it’s better to opt for options that will help you feed your fish while you are gone.


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