Food and Nutrition, Pet Health

How Long Can Your Tropical Fish Survive Without Food?

This is a question that many good aquarists contemplate when planning a vacation or time away from home.

Of course, you can always take your fish with you. If we are honest, however, it is neither recommended nor practical.

You are, therefore, faced with the question of whether your beloved fish will be all right while you are away, and whether that will be achieved by leaving them under the care of someone else or on their own.

It is important to make necessary preparations if you want your fish to be alive by the time you get back from being away.

The easiest way to make sure your fish won’t go hungry while you’re gone for an extended period of time is by using an automatic feeder.  These can be picked up for around $20.  Here’s a highly rated option for around $20 on Chewy:

Let’s look at a few things to consider when trying to determine how long you can leave your fish without a food supply.

Age of the aquarium setup

This is one of the most important factors to consider when planning your vacation. Is it more established, older or a relatively new model?

While there are certain exceptions to keep in mind (and we will discuss them), the more established the inhabitants and the older an aquarium is, the longer the aquarium can go without worrying about the potential disaster.

The reason behind this is that the fish already know how to survive in the aquarium, are healthy and more importantly, all the members of the community get along just fine. If well established, an aquarium can run for longer periods of time on auto-pilot.

When it comes to aquariums that are newer, there is a good chance that an ecological balance between aquarium volume and fish load as it relates to water changes as well as filter maintenance hasn’t been reached.  You should also be sure that the water temperature is high enough for your tropical fish.  All tropical fish tanks need an aquarium heater.

Behavioral overstocking may be present in the fish tank i.e. territoriality and aggression or in terms of production of waste. It is important to have knowledge about the setup of your fish tank as it will make it easier for you to accurately predict how long your fish can survive while you are away. It is considerably riskier to leave a fish tank that is still finding its balance unmanned.

How long will you be gone?

Another important factor to consider is the amount of time that you will on holiday. You may not need to need to do any preparations if you will only be away for a long weekend. Many aquarists leave their fish tanks without food preparations for two to three days.

Most types of fish can go for at least that long without needing to feed. However, more elaborate preparations will be necessary if you will be gone for longer.

Some of the steps you can take to ensure that your fish remain healthy for the duration of the vacation include cleaning the filtration system and performing a partial water change a few days before leaving.

This is because you will need a few days to ensure that filtration system is working as it should and that there aren’t any additional problems.

So how long can tropical fish survive without food?

This is arguably the most common question among fish keepers who are planning to travel in the near future. Many tropical fish can go for long time without eating.

The exact length of time that they can go without food depends on several factors, some of which have discussed above. Other factors include the size of the fish, their age and whether they are omnivorous or herbivorous.

While there are certain exceptions, the general rule of the thumb is that older and larger fish can go longer without food as compared to younger and smaller fish. This is because older and larger fish often have more body mass as well as fat reserves. As such, an adult chocolate cichlid will survive longer without food as compared to a golden pencil fish.

It is also important to note that by nature, carnivores do not eat every day. In fact, they can endure a season when food resources are scarce in the wild. On the other hand, herbivores have to feed every day. In fact, it’s pretty much all they do. Such fish feed on plant matter that is, under normal circumstances, hard to digest.

They, therefore, have to eat a lot of it so as to get enough nutrition.

Carnivorous fish in an aquarium handle longer periods without food better than herbivorous fish. A trial fasting period before going for a vacation can help you accurately determine how long your fish can go without food.

Treat the fish tank as if you were not around.

Don’t perform any maintenance or feed the inhabitants when checking on it every few days. You will be able to observe how the inhabitants hold up as the days go by.

Most tropical fish kept in home aquariums can survive a few days without feeding. If you are going to be away for longer than that, it is only fair that you make feeding arrangements for them.

The kind of preparations made depends on a lot on the species involved. For instance, healthy cichlids can go for as long as ten days without food while baby fish can only last a day or two before they require food.

The good news is that there are a few tricks you can implement to extend the interval between meals while ensuring that your fish stay healthy.

Turn down the temperature

This reduces the rate of metabolism of your fish, thus reducing their need for food.

Shorter than normal daytime: If you put the aquarium lights on a shorter than normal daytime timer, you will be limiting activity that would increase the need for feeding.

Are there other options?

If you keep young or small fish in your aquarium, there are some measures you can take to ensure that they are fed regularly while you are away. This may pose a few challenges, especially if your fish have special dietary needs.

A good example of such fish is the newly hatched brine shrimp. Commercial vacation feeders may not always be the best, and in such cases, a commercial fish sitter or a trusted friend will come in handy.

Fish sitters

A well-prepared fish sitter with clear instructions on how to take care of your pet can make the difference between life and death for your fish. There are many types of fish sitters including a relative, a friend or a neighbor’s kid who wants to earn extra pocket money.

For an affordable fee, you can also enlist the help of commercial fish sitters who make a living servicing and taking care of aquarium in schools, hospitals, and offices to do the same for you while you are away on vacation.

One of the important things that the potential fish sitter should be aware of is the size of your fish tank. The sitter should also be made aware of exactly what you need them to do. Don’t just expect them to refill the CO2 canister or harvest the brine shrimp.

It is important to make that job as easy for them as possible.

You also want to make sure that you sitter knows how often the aquarium should be tended to. Once every three or four days should do. That is, of course, unless you have several aquariums filled with baby fish.

Not feeding the fish daily helps reduce the amount of waste as well as the chances of overfeeding. Other specifications to be made to the sitter include what and how much to feed your fish.

If possible, write down all of the above in case the sitter forgets something. Also, leave contact details so that you can be reached easily in the event of an emergency.

Vacation feeders

Another great alternative if you cannot get a fish sitter is a vacation feeder. This is a commercially packaged slow-release feeding blocks. Vacation feeders come in a variety of shapes and sizes and are designed to feed your fish for specific periods of time. The main disadvantage of these is that the food they contain may not be what your fish are used to consuming.

To curb this, try exposing your fish to the specific feeding block you intend to use while you are on vacation. Stop feeding them as you normally do and place the feeding block in the aquarium.

Automatic feeders

These are designed to hold and dispense free-dried or dry food items. They come in a wide variety of designs and can be programmed to feed your fish once daily or every few days. They work by rotating a compartmentalized drum or plate via a timer.

Here’s the highest rated and best value automatic feeder we could find:

It’s easy to install and program and has a nice digital display.  You can adjust the amount of food given in each feeding, and it can keep your fish fed for weeks.

While the idea of automatically feeding your fish is appealing, it is important to understand that in case the filter stops working, continued dispensing of food will result in a polluted aquarium. This may ultimately cost your fish their lives.


With a little preparation and planning, taking a vacation should not be a life or death situation for your fish pets.

While many fish can survive a few days without food, the most important thing to remember is that maintain a regular maintenance schedule as well as avoiding overstocking of the aquarium will go a long way in ensuring the health of your fish when you go on vacation.