How long can Fish go without Food?

We get it–once in a while, something comes up, and you can’t always stick to your fish feeding schedule. But being held for a few hours at work is one thing; going away for an extended vacation is another.

So, being the responsible aquarist you are, you ask: how long can fish go without food exactly? Will you still have a tank full of healthy and happy fish after leaving them for, say, a weekend? Do you need to call in favors from friends and family to check in on your fish while you’re away?  We go down to the nitty and gritty to answer these specific questions for you.

The Short Answer

As fragile as they may seem, fish are actually hardy creatures. They have an impressive ability to endure long periods of fasting.

The general rule is that the bigger and older your fish is, the more likely they are to survive without food for a longer period of time. This means that in some cases, you can leave your fish without sustenance for up to 14 days without lasting consequences to their health.

However, various factors need to be considered if you plan on leaving your fish for an extended period. We’re talking about the type of fish you own, their age and health, your aquarium’s setup, etc. For example, if you own younger fish and herbivores, then the chances of them surviving a weekend without feeding may be slim.

This graphic shows popular breeds of fish and how long you might expect them to go without food.

The Long Answer

Still can’t seem to fathom the idea of leaving your pets without food for more than a few hours? We created this guide for every conscientious aquarist out there. Here we have outlined the factors for survival, the fasting tolerances of common aquarium fish, and possible feeding solutions for those planning on going on an extended trip.

Factors that determine how long my Aquarium Fish survive without Food

Sure, there may be a rule of thumb that determines the length of fish survival sans food. But naturally, we want to make sure that we’ve covered all bases. In this section, we discuss the factors that need to be considered when determining the length of said survival.


What Type of Fish do you have?

As an aquatic life enthusiast, you may already know that fish can be distinguished (and are often categorized) based on the type of food they eat.

We have carnivores who prefer to eat meat-heavy diets. The herbivores only rely on algae and plants to sustain them. The omnivores eat both meat and plants in the aquarium. Lastly, the limnivores favor food that is mud-based.

First, consider the type of grub that your pets eat to determine their meal frequency. This should give you a pretty good idea of how long they might survive without food. For example, carnivorous fish types will likely fare better without food for longer because, even with you at home, they’ve managed to survive days in between hunting their prey. They are basically designed by nature to survive despite the scarcity of food.

Your less resilient herbivores and limnivores, on the other hand, need more frequent feeding. They often graze and become hungry much more quickly.

So, in terms of leaving your fish alone for a prolonged period, the carnivores of the aquatic world seem to have a leg up in the game of survival.


When did you set up your Aquarium?

Yes, the setup of your aquarium matters. If you’re planning on taking a vacation or going on a business trip, this should be one of the top things you consider. Is your aquarium setup fairly new? Have you recently revamped your little fish sanctuary? Or has it been able to stand the test of time in terms of strength and resiliency?

You might think a new setup is less worrisome on the get-go because of new equipment and whatnot. However, older tanks are actually much more reliable in terms of housing your fish.

Consider this: ecological balance in an aquarium cannot be achieved overnight. The population of fish in a new aquarium may take some time to be at an optimum level. So, in an older aquarium setup, ecological balance will likely already have been achieved.

This is because your fish tenants will have already acclimatized to the aquarium’s environment. Not to mention, all the fish in the tank will also have already gotten along with each other by now and can live harmoniously even in your absence.

In short, your pets in tried and tested aquarium will have better chances of survival because they’ve already managed to make it their home. They will already know how not just to survive but thrive in it.

It is also a factor if you have plants in your aquarium. They can increase the chances that herbivores survive a long time without food because the fishes can eat some of them. So they will have some food even if you can not feed them for days.

What are the Fasting Tolerances of popular Aquarium Fish?

By now, we’ve learned that some types of fish will have better chances of surviving without food for longer.

In this section, we’ve outlined popular breeds of fish and how long you might expect them to go without food:

  • Betta Fish: 10-14 days
  • Goldfish: 10-14 days
  • Neon Tetras: 7 days (up to 3 weeks in planted aquariums)
  • Platies: 10-14 days
  • Cory Catfish: 7-14 days
  • Guppies: 10-14 days
  • Mollies: 10-14 days
  • Zebrafish: 7-14 days
  • Tangs: 7 days
  • Firefish: 7-14 days
  • Clownfish: 7 days
  • Butterfly Fish: 7-14 days

How can I feed my Fish when I am on Vacation for a Week or longer?

As committed as you may be to your aquatics pets, it might not be in their best interest (and yours) to bring them on vacation. Still, while you’re lounging in your dream destination, you also don’t want to worry about the wellbeing of your fish constantly.

If the sections above have managed to assure you that your fish will survive with just a few days of going without food, then all may already be well and good. However, if you have learned that the type of fish you have may not be as resilient as other fish, keep on reading.

If you need to leave longer than the perceived fasting tolerance of your fish, don’t fret just yet. There are still certain measures that you can do to ensure that your pets don’t go belly up in the duration of your vacation. Calling in favors from friends and family may work for you. Another solution is to invest in automatic feeders for the residents in your tank.

Automatic feeders – they are exactly what they sound like. The best ones in the market dispense dry food to your beloved pets based on the feeding schedule that your fish have already been accustomed to.

These feeders are attached to your tank and can easily be programmed to follow a reliable feeding program for your fish. You can set it to dispense food daily or once every few days.

Freshwater, reef, or marine – it really doesn’t matter what type of fish your tank carries. Your automatic fish feeder will cater to every type of fish in your aquarium. The more impressive brands allow you to dispense food for up to 6 weeks. That’s a month and a half of blissful vacation, free from pet parent guilt–what more can you ask for?

A little bit overwhelmed by the plethora of automatic feeders in the market? Here are our top two choices out of the dozens of automatic feeders in the market:


The Eheim Everyday Fish Feeder

Aquarists all over the globe have spoken–Eheim is easily the top feeder for most of us. It’s reliable and, more importantly, offers good value for your money too. Sure, it may cost a little bit more than the cheaper and lower-end products, but the few extra bucks are well worth it.

It typically dispenses pellets and even dried worms, set at the portion sizes and time you will need to indicate. We love how you can feed your fish up to 4 times a day with this (not that you need to, of course, but it’s still a good feature to have).


Fish Mate F14

What we love about this automatic feeder is its ability to stock food in its 14 different trays. This means that come feeding time, it can release multiple types of food to your pets, allowing them to enjoy mixed sustenance of fish flakes, pellets, algae wafers, and what-have-you.

Through this product, you can even set your feeding for alternate days. As far as we’ve checked, the Fish Mate F14 is the only product that allows you to skip meals and lets you feed your fish every other day. As accurate as this product is, however, it does tend to hold less food than you would typically be able to dispense with another automatic feeder.

A fair word of warning, though–as convenient as automatic feeders may seem, it is still important to practice responsible fish ownership. By this, we mean that you are still expected to do your due diligence, such as checking your tank’s filtration system and making sure that it still works. After all, the last thing that you want to do is to dispense food to a polluted tank, right?

Conclusion – How Long can Fish go without Food?

We’ve learned that fish can be quite resilient creatures that have a considerably impressive fasting tolerance. Some can go for a few days without eating while others may need more attention, more often. How resilient they are and the specifics of their fasting tolerance, however, is subjective to their breed as well as the age and condition of your aquarium.

Now that you are armed with the right know-how, you can go ahead and rest easy in making the right preparations to ensure that your fish will be happy and healthy even when you are away.


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