How Long Can Your Aquarium Fish Go Without Food And Why?

logo by Editorial Staff | Updated on August 5th, 2022

Exact time frame: 2-3 days

When you decide to take a trip, you often wonder how your fish will live for an unknown period of time while you are away.

clear glass fish tank with blue fish

Of course, you can’t bring them about with you, so it’s always good to investigate how long your fish can survive without eating.

This is mostly for your fish’s protection and your peace of mind while you are not present.

Furthermore, you mustn’t have a disaster at home while away from your profession.

How long can a fish go without food?

It is critical to understand how long your fish can go without eating.

As a result, you must conduct a study and be certain. Many aquarists often leave their fish for 2 to 3 days.

Thus, the length of time your fish live is determined by a variety of factors, including:

The length of your absence

This is a very important thing to consider before departing.

The length of your absence is important, but if you’ll be gone for 2 to 3 days, there’s no need to worry because many fish can last that long without feeding.

You need to know how long it will take you to decide whether or not you will leave them in the care of someone.

Filtration cleanliness

Keeping your fish clean before you leave for a while will stay healthy for a decent amount of time.

Cleaning your filter system and ensuring their water is safe before you go is typically advised.

It also aids in the prevention of problems such as suffocating your fish.

What types of fish do you have?

Different varieties of fish are classified into four distinct groups based on their food.

Herbivore, omnivore, carnivore, and limnivore are the four major groups. Carnivores, such as cichlids, devour meat, whereas herbivores, such as tangs, eat plants and algae solely.

Omnivores typically eat both meat and vegetables. Limnivores eat mud-based foods. In brief, the feeding frequency of the fish is determined by the species of fish.

Carnivores, on average, can go longer without eating than other fish species.

They’re equipped to withstand protracted times of food shortage since they may go days without capturing prey.

Other types of fish, particularly omnivores and herbivores, require food more regularly to survive and therefore spend more time consuming or searching for food.

The size of your fish

Small fish, compared to huge and elderly fish, cannot go long without feeding due to their body bulk and the lipids in their bodies, which allow them to survive well without food.

What is the level of activity in your fish?

The length of time your fish can survive without food is highly dependent on its metabolism. Smaller fish are more active, which implies they require more food than larger, slower fish.

Tetras and Rasboras, for example, are small, schooling predators that are always active. It’s part of their attractiveness that they dart around, nibbling at each other and investigating their surroundings!

In the wild, these fish continually “graze” on plankton, bug larvae, and other food that drifted past. They get a massive meal all at once in aquariums, which fills them up for a few hours. Even so, you’ll need to feed these guys twice a day, if not three times a day!

The faster your fish’s metabolism, the warmer the environment. Many tropicals, such as Danios and White Cloud Minnows, can also thrive in cooler water.

In colder environments, we should feed them less often or give them less food per meal (1-2 times per day). You’ll end up with either obese fish or uneaten food.

Is your fish a vegetarian or a carnivore? Herbivores graze incessantly because plants are numerous but poor in nutrients. They require a huge amount of this lower-calorie diet to maintain their weight. On the other hand, Carnivores can consume a single meal and digest it for a long time before eating again.

The aquarium setup’s age

It is the most important aspect to consider before leaving your house.

Typically, the bigger the aquarium, the longer your fish may survive, giving you no need to be concerned when you leave.

This is mostly because aquarium fish often know how to navigate; they are usually healthy and get along extremely well.

Limit the temperature: If you want to reduce the metabolism of your fish, you must lower the temperature rates, which reduces their demand for food.

You will be restricting cineraria, which will increase their requirement for food.

Getting Your Fish Ready for When You’re Away

If you want to leave your fish for an extended time, you need to take certain precautions to ensure their well-being when you return.

Treat the Aquarium as if you aren’t there.

You must acclimate your fish to particular surroundings so they do not feel a significant shift while you vacation. Maintain a ‘hands-off’ approach for a time to monitor your fish’s behavior.

For a period, don’t feed or maintain the tank to check how the residents are faring. This plan should be carried out a few days before you travel, as well as the previously specified water and filter changes.

Reduce the Temperature

Lowering the temperature affects your fish’s metabolic rate, lowering their requirement for food. You’ll most likely set a timer for the aquarium lights before you leave.

Set your fish tank lights to a shorter than usual daytime timer to limit the fish’s activity and reduce the demand for feeding regularly.

Are there any other choices?

If you maintain young or small fish in your aquarium, you may take certain precautions to guarantee that they are fed regularly while you are gone. This may provide some difficulties, especially if your fish has unique dietary requirements.

The newly born brine shrimp is an example of such a fish. Commercial vacation feeders aren’t always the greatest option, so a commercial fish sitter or a trustworthy friend will come to help.

sitters for fish

A well-prepared fish sitter with clear instructions on how to care for your pet can be the difference between your fish’s life and death. Various fish sitters, such as a relative, a friend, or a neighbor’s child, are looking for extra pocket money.

You may also hire commercial fish sitters, who make a livelihood servicing and caring for aquariums in schools, hospitals, and workplaces, to do the same for you while you are on vacation for a reasonable charge.

The size of your fish tank is something the potential fish sitter should be aware of. The sitter should also be made aware of what you want of them. Expect them to do more than replenish the CO2 canister or collect the brine shrimp.

It is critical to make their task as simple as feasible for them.

You should also ensure that your sitter understands how frequently the aquarium should be tended to.

Every three or four days should be enough. That is unless you have many aquariums full of newborn fish.

Not feeding the fish regularly reduces waste and the possibility of overfeeding. Other instructions to the caretaker should include what and how much to feed your fish.

If possible, write everything down in case the sitter forgets something. Also, give your contact information so that you may be quickly reached in an emergency.

Feeders on vacation

A vacation feeder is another fantastic option if you can’t find a fish sitter. This is a slow-release feeding block that has been commercially marketed.

Vacation feeders come in various forms and sizes and are intended to feed your fish for set periods. The main disadvantage is that the food they contain may differ from what your fish are used to eating.

To counteract this, try exposing your fish to the specific feeding block you intend to use while away. Place the feeding block in the tank and stop feeding them as usual.

Feeders that operate automatically

These are used to retain and deliver free-dried or dry food. They come in several styles and may be set to feed your fish once a day or every few days. They operate by using a timer to rotate a segmented drum or plate.

It’s simple to set up and configure, and it has a good digital display. You may customize the amount of food delivered in each feeding, and it will keep your fish nourished for several weeks.

While the thought of automatically feeding your fish is intriguing, it is critical to remember that if the filter fails, continuing feeding will result in a dirty aquarium.

This might lead to the death of your fish.


The length of time your fish may survive is determined by the elements listed above, so if you put them into action, you can be confident of favorable outcomes.

Based on the facts above, you should have a good idea of how and why your fish will take that long to live.


Editorial Staff

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