How Long Can Fish Go Without Eating Any Food? (+ Chart)

You are in control of your fish tank, right until you have to leave town for a few days.

But how long can your Betta fish or Goldfish go without eating? Will your fish be able to live a couple of days without being fed? Would the aquarium survive on its own for a whole week? If so, exactly how long can your pet fish go without food and will they turn ill during this period? Is there a way around starving them if you’re leaving for a vacation?

How long can pet fish go without sustenance?

In the wild, fish rarely get to eat a meal each day. Some of them will experience long periods without consuming any food.

For example, the female mouth-brooding African Cichlid can go up to a month without eating when holding baby fry in her mouth.

That being said, here’s how long the average freshwater fish can go without food:

A healthy, grown-up aquarium fish can go from 3 days to 1 whole week, without eating any food. Some fish species can even live for more than 2 weeks without eating.

Whether in nature or in an aquarium – an adult fish has sufficient body mass and fat reserves to skip a couple of meals once in a while.

Therefore, if you are planning a weekend away, you don’t have to worry if your fish would survive without being fed.

The truth is we tend to overfeed our pets. We forget they originate from surroundings where they don’t have their meals regularly.

When it comes to fish fry, however, this is not the case. When fish are first born they need to eat a few times per day.

Nutrition plays a crucial role in building up their bone strength.

Not feeding baby fry enough may cause deformities, sickness, or even death.

Overview chart for individual fasting tolerances of popular freshwater fish

Although fish are hardy in general, their fasting tolerance varies depending on their breed.

Take a look at a chart that lists the number of days popular freshwater fish can live without food:

Type of fish: Period it can safely live with no food:
Betta 1 to 2 weeks
Goldfish up to 10 days
Koi Fish up to 2 weeks
Guppies 7 to 10 days
Danios up to 14 days
Tetras up to 10 days
Platies between 10 and 14 days
Mollies up to 2 weeks
Angelfish up to 1 week
Rasboras up to 1 week
African Cichlids up to 10 days
Plecos 10 to 14 days
Oscars up to 2 weeks
Swordtail fish maximum of 14 days
Corydora catfish up to 2 weeks
Barbs up to 14 days
Discus up to 14 days
Loaches up to 10 days
Gouramis up to 2 weeks

The list above is based on my discussion with other fish keepers with hands-on experience and my own observations with some of these fish.

Despite all the evidence that fish have higher fasting tolerance than we think, I do not recommend leaving your pets without food for this long.

Such an endeavor is hazardous and you might end up losing your small friends.

Although no one can precisely tell the time a fish can survive without eating, there are some additional factors you might want to take a look at.

Are your pet fish herbivorous or carnivorous?

The first group eats plants and algae. The plant material herbivores consume is harder to break down and they need food more often in order to get sufficient nutrition.

A good example of aquarium herbivores are some types of plecos, the otocinclus and some other fish that may eat algae.

Carnivores eat meat, and they often spend days without eating in the wild because of an unsuccessful prey hunt. Therefore they are able to endure long periods with no food.

What are the size and the age of your fish?

Bigger and older fish are hardier, as they have enough body mass and fat reserves to use in case of extended periods of hunger.

For example, Gourami fish will last longer without food than a small Guppy fish.

There are some tricks you can use before you leave, which will help reduce the appetite in fish.

It’s well known that most fish are not active during the night.

You can set the light timer to 6 or 8 hours, instead of 12, for example.

Shorter day time will diminish their activity and their need for a meal.

Another trick you can use is to slowly lower the fish tank’s temperature.

Be careful not to lower it with more than 2 degrees and do make sure the change is gradual

After all, you just want to slow down their digestive processes, not to send them to the North Pole.

A good way to feed starving pet fish while you’re on a vacation

Knowing that fish are tougher than we tend to think, you can now rest assured that leaving your aquarium without food supplies for a weekend is not an issue.

However, that’s not really necessary.

Take a look at how to properly feed your fish when you are on a vacation:

The best way to feed your pet fish while you are away or on vacation is by using an automatic feeder. With one such device, you will be in control of the food schedule and serving amounts. That way you can be sure your fish will not only survive but live healthy in your absence.

Of course, you can ask a friend or a relative to feed your pets.

However, with this option, you risk the caretaker overfeeding your aquarium fish.

In this case, you might end up with an ecologically imbalanced fish tank, which can lead to a plethora of other issues such as a spike in ammonia levels and more.

As I have mentioned before in my articles, I have been using an automatic fish feeder for a couple of years now. I was lucky enough to find the most suitable one for my needs within short research. It turned out to be the one Eheim manufactures. I first got it to avoid overfeeding my fish.

However, I realized its real potential a few months later when I had to go on vacation for 6 days. I set the schedule for this amount of time (very easy to do) and went away without any concerns. When I got home, I found all of my fish in good health, well-fed, and the aquarium was as clean as I left it.

I would also suggest that you buy Eheim’s food station that goes along with the feeder. It prevents any scattered food particles on the water’s surface and lets the meal soak properly before sinking.

To simplify the process of feeding your fish while you are away, you can try this Vacation Pyramid as well. I’ve never used it, but I know a few people have, and it worked fine for them.

When you drop the pyramid in the tank, it slowly releases food over time.

However, if you choose this option, you will not be able to control the amount of food the fish consume. It might finish before you come back, or it might remain uneaten.

The pyramid might release lots of organics in the aquarium, hence algal growth will be encouraged, and water could turn green.

Make sure to use this type of feeder in a fish tank with a well-working filtering system.

Final words

Healthy fish can safely go with no food for up to a week without this causing an issue to their well-being.

If you need to be away for longer or have fish fry in the aquarium, you should likely make some preparations before leaving.

Furthermore, it’s advisable to get an automatic fish feeder to ensure that your pet fish can eat regularly while you’re gone.

You are now ready to go and enjoy your vacation.

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