How Long Can Fish Go Without Food in an Aquarium?

Lauren Kiekbusch
How Long Can Fish Go Without Food in an Aquarium

I have a friend who is very fond of his fish. We are very close friends, but we never got to go out for a tour or a long vacation. At most 1 day or so, that’s it. The reason he was very concerned is his fish will starve.

From his point of view, I understand how much he loves his fish. I tried to show him some Google search results, which said, fish may go from 3 days to 1 whole week to a safe, grown-up tank, without food. Few species of fish can also survive without food for more than two weeks.

If in nature or at an aquarium, adult fish have enough body weight and fat stores to consume a few meals from one time to another.

But nothing could move the foundation of his belief, that if he went away, his fish would starve. From this idea, I came up with an idea and researched it for a bit. This article is all about a fish’s food reservation in its body, the limitation of days of no food, and even if you are away, how your fish could be fed.

I hope this article will help all the pet fish lovers along with my friend. Let’s get started. Before going straight to the main point, let’s know about some important facts. Maybe these facts will help you to not read through the whole article.

Also worth reading;

  1. What Aquarium Fish Don’t Have Scales?
  2. Is Clownfish A Freshwater Or Saltwater Fish?
  3. Freshwater Fish for 10-Gallon Tank: Which Are The Perfect?
  4. What Size is a 20-Gallon Fish Tank? (Dimensions)
  5. Aquarium Heater Size: What Size Heater Do You Need in a Fish Tank?

How Aged Is Your Aquarium?

Apart from the aquarium, think about you and your living place. If you are at home, you can find anything even if there is no light or you are blindfolded. Because you know the place very well.

how long can fish go without food

An ecosystem is of great importance for fish. The more individuals and the older an aquarium is, the longer the aquarium can do without concern for a possible catastrophe.

Although some exceptions must always be taken into account. The ecological equilibrium between the aquarium and fish load is extremely probable for the more recently built aquariums. 

The explanation for this is that the fish are now able to live in the tank, are stable, and above all, all members of the population are doing well. It is easier to foresee how this will happen when you leave it alone for a certain time.

With some information and experience with your specific set-up. It is far more dangerous to abandon an aquarium “finding its balance.”

Species Of Fish In The Tank

Of course, fish types are very important too. There are some fish, which can eat or sustain on their own by eating from the ecosystem of your tank if the tank is old enough. Some fish always rely on food that is provided for them.

Some fish demand food more frequently to survive. Especially Omnivores and Herbivores, spend more time eating or looking for food. 

Carnivores tend to survive longer without feeding as compared to other fish types. Since they can go days without catching prey. They’re designed to survive through long periods of food scarcity. 

Just like this, you may have fish that have to be fed meat or live food, and you can also have some which rely on food from the mud or we can say the gravel.

The Time Of Your Absence

That’s why you must care once you fill your fish tank with the food you need. If you only go for a weekend (or long weekend), if you have an old fish tank set up, you will have to do nothing in planning. Many seasoned fishermen leave their fish regularly for two to three days without having food. 

To guarantee, though, that your fish stay safe over the weekend away. You need a few days before you’re leaving to clean the filtration device and adjust the water.

Training Your Fish

This fact is not a great option for those who are beginners or don’t have any experience or have a new setup. Yet this option is not a bad idea if you consider it.  

Just like all other pets, they can be trained too. Maybe they are not as intelligent as dolphins but they can understand the slight changes in the habitat. Most likely if you start to treat your fish with less or no food for different sessions may help them to develop themselves without food.

Don’t feed the tank or hold it for a bit to see how the people cope. This schedule should be introduced a few days before leaving and before replacing the water and filter, as previously stated. But keep a record of stopping food supply or else you may end up with fish with bad health conditions

Another factor that may work. Just think of yourself having the mood of eating good food. It also depends on the temperature around you as much as it depends on your hunger. Your fish are not so different. If you provide them with proper food and a suitable temperature they are most likely to become healthy.

Take that away from them and they are most likely to hibernate themselves for a while. No, we are not talking about the “ Ice Age” Type of hibernation. A slight one, where the fish may isolate themselves to conserve energy as they are cold-blooded species.

how long can fish go without food

How Long Can Your Fish Live Without Food?

You would not have to worry if you are going to be not around for 2 or 3 days. If you are about to leave on Friday, feed them on Friday morning and you will find them as you left them on Sunday.

If we speak of goldfish, since they are the most common fish as pet fish, they can be eight to 14 days without food. They scoop their aquariums and feed their algae during this period. Goldfish will go without indeterminate feeding in ponds depending on size and available algae and insects. 

How long can your fish Live without Food

There is an extreme case in which two records live for 134 days in Christchurch, New Zealand, without shelter, after a major earthquake. There were entirely no city borders to no one eating or inspecting them. These fish possibly lived by feeding on algae and the occupants of the tank. 

Can you recall the fact that the temperature decreased? After a few days with no food, multiple fish act differently. Some fish may die while others hibernate. Some fish may die. It’s important to find someone to inspect your fish if you are gone longer than two weeks.

It might not be a healthy health option to let your fish live for a long time without food. Food shortages will stress your goldfish, leading to other health problems. 

The tank water is uncluttered and there is little to think about as long as you have fed your fish properly. Your fish should be all right if you leave for up to 2 weeks.

Feeding Your Fish While You Are Away

Though your fish are likely to survive even if you are away for two weeks. But remember the fact that we mentioned there is still a risk of losing some fish due to starvation. Not all fish can survive.

For that, you have to take some preparation both manual and automatic. It may seem impossible but let me assure you, it is difficult, not impossible. Let’s get started with the procedures;

1. Manual Feeding System

Remember I mentioned my fish-lover friend? This is the most common procedure you can follow. If you are living with someone you just simply tell them to feed your fish at a preferable time. But how certain are you that they will feed them on time? 

From my personal experience, I had to call my friend for the measurement of food, for the timing, and the types of food. Even there were some moments like this when I was not home. Over time I came up with an idea of the timing and food measurements.

But you really can not expect that from any person who is going to feed the fish for the first time. They could excess it which may lead to cloudy water or acidity among fish. Of course, you always have the option of Fish Sitters.

No doubt they are very professionals, yet these fish are not theirs. And not many people can afford fish sitters every time they go outright?

2. Automatic Feeding System

In my opinion, this option is the most affordable and easiest process you can follow.   

A variety of brands are available for the home aquarium, battery-powered, or electric automatic feeder. All are meant to carry and provide dried food materials such as flakes and pellets. The choices are different, but the majority can be configured to provide fish food for up to two weeks twice a day. 

They are usually powered by batteries or electricity and can be used to periodically release products such as flakes, pellets, or dried fruit. For up to two weeks, most will feed your fish. 

While the idea to add an automatic feeder may be enticing, it is important to understand that food is distributed in the contaminated aquarium in case the filter fails to operate.

The condition of fish can also be life-threatening. So when picking the right one you have to be very patient. Here we have arranged a list, from where you can directly access and buy the best ones. 

Automatic Feeders Features Buy on Amazon
Eheim Automatic Feeding Unit
  • Easy digital LCD programming for up to a maximum of 8 feedings per day
  •  Easy to set-up and use and also includes the Easy Start Guide
  •  Manual release button permits feeding outside pre-programmed times
  •  Integrated fan and ventilation system keeps the food dry
  • An adjustable slider allows you to set desired portions
  •  Splash-proof buttons
Click Here
Fish Mate F14 Aquarium Fish Feeder
  • Reliable and accurate quartz timer
  • Serves up to 14 individual meals while you are away
  • Food is served over several hours – keeps fish active and reduces
  • The danger of overfeeding
  • Easy to use timer provides from 1 to 4 meals per day
  • Over 1 year’s continuous use from 1 x AA battery (not included)
Click Here
Auto Fish Feeder
  • Programmable
  • Two Different Fixed Methods
  • Moisture Prevents Design
  • Easily Add Food
  • Large Food Capacity
Click Here
Juwel Automatic Aquarium Feeder
  • Wipe clean
  • Juwel automatic feeder for all aquariums.
  • Batteries included.
  • Item Dimensions LxWxH 0.39 x 0.39 x 0.39 inches
Click Here
PORSCHE Automatic Fish Feeder 
  • Material: Plastic
  • Type of battery: 2*AAA batteries(Included)
  • Unit Dimensions: 4.3*4*2.5in / 11*10*7cm
  • LCD Screen Dimensions: 1.1*0.5in / 2.6*1.3cm)
Click Here

3. Vacation Pyramid Feeder

Now, this is a product that I have come up with several reviews among pet fish owners who travels a lot. When you are about to leave home, just put it in the tank and it will gradually release food for the fish. In this manner, you will not have to use electricity or invest in AAA batteries. 

Along come the disadvantages. You will have no control over the food flow. You could overdo it with the food provided, which may lead to cloudy water. Most reviews are in support of this product. Most of the time, the pyramid may dissolve or be eaten, or you can take out the rest after you return.

Procedure After Returning Home

Very few sad moments are there as the ending of vacation. Yet, it helps us to learn many things. You will need to prepare to change the water and clean the filter reasonably quickly after you return, based on how much time you’re away from home.

In terms of upkeep and feeding, it is necessary to maintain aquariums on a daily schedule as quickly as possible. It is possible that even after you had arranged all the necessary procedures your fish did not survive.

Don’t get disheartened. This could be a very good lesson. Maybe your food course was a bit off. Maybe it’s the temperature or could be anything. Figure it out and you will have better results in the future. 


The impression of a holiday with a little preparation and planning doesn’t need to be a lifetime and death test or a source of discomfort to your fish in a time of relaxation.

The best advice I will give is not to exaggerate your tank and maintain a daily cleaning schedule, against all my suggestions: two aspects that can take you a long way to get your fish back home.

The first phase is a properly kept tank containing good, well-fed fish. This helps them to have their fasting time without pain. On your return, you would be pleased to see you.

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