How Long Can Fish Live without Food?

We’ve all been there: preparing for a vacation, but wondering what to do with our pet fish while we’re away. If you don’t have friends or family to feed them regularly, you have no other option than to leave them without food for a while.

Before you panic and envision your finny friends belly-up, here’s the truth: most fish can survive longer than you think without food. But there’s a catch (of course, there always is in fishkeeping!).

How Long Can a Fish Go Without Food?

The answer depends on several factors, like:

  • Fish species: Coldwater fish like goldfish are more resilient than tropical varieties. Bettas, however, can even last weeks – I have an in-depth article on the matter here.
  • Age and health: Young, healthy fish generally handle periods without food better than older or frail/sick ones.
  • Water temperature: Colder water slows metabolism, so fish burn energy slower (so keeping the temperature to the minimum so your fish can survive will help).
  • Aquarium environment: A clean, well-maintained tank reduces stress and helps fish conserve energy.

With all these in mind, healthy adult fish can last around 7 days without food, some even up to 2 weeks. But remember, this isn’t ideal for them and they shouldn’t go often without food for such long periods.

It’s like asking if you could survive a week without eating, as a human. Yes, it is possible, but not good for your health.

Depriving your fish of food for extended periods weakens their immune system, stresses them out, and stunts their growth.

So if you like going on vacation often, you do have to find some alternatives to keeping them well fed – like using automatic fish feeders like my recommended Petbank Fish Feeder.

How long will the most popular fish breeds go without food – comparison table

To make things easier to understand and follow, I have created this table below, including some of the most popular freshwater aquarium fish types and how much they can live without food.

Fish BreedTypical Survival Time Without FoodNotes
Goldfish5-7 days, up to 2 weeksMore resilient than tropical fish due to slower metabolism in cooler water.
Betta7-10 days, up to 2 weeksKnown for their hardiness, but not ideal due to small bowl setups often used.
Neon Tetra4-7 daysSensitive to water quality changes, so regular care is crucial.
Guppy4-7 daysActive fish with higher energy needs, so shorter survival time.
Platy4-7 daysSimilar to guppies in terms of needs and survival time.
Molly3-5 daysLivebearers with higher protein requirements, making them more susceptible to fasting.
Swordtail3-5 daysSimilar to mollies in terms of needs and survival time.
Zebra Danio3-5 daysActive fish with higher energy needs, so shorter survival time.
White Cloud Minnow4-7 daysPeaceful and hardy, but still require regular feeding.
Corydoras Catfish5-10 daysBottom feeders that can scavenge for leftover food, extending their survival time.
Angelfish3-5 daysLarger fish with higher food requirements, making them more sensitive to fasting.

Preparing Your Aquarium for a Longer Leave

different types of fish in an aquarium
Different types of fish, each with individual needs.

If you know well in advance that you’re going to be away for a longer period of time, here’s how to best prepare your aquarium and the fish inside:

  1. Feed them well before you leave: Give them a hearty meal before you leave. But DON’T overfeed them – too much extra food can rot and destroy the quality of the water.
  2. Partial water change: Remove 25% of the water and replace it with fresh, conditioned water one to three days before leaving. This reduces waste buildup and improves water quality.
  3. Skip the algae wafers: These can decompose and pollute the water while you’re gone. If you REALLY want to use one, choose a small size and be 100% sure it’s the highest possible quality, guaranteeing that it won’t pollute the water.
  4. Consider an automatic feeder: These handy devices dispense small amounts of food at programmed intervals. My favorite is the Petbank Automatic Fish Feeder.

This is everything that you can do to prepare your tank in advance for an extended leave.

Some people recommend feeding your fish more than usual for a few days before leaving, as they get fatter and can handle the following lack of food easily.

I never noticed fish getting fat – they always seem to eat just as much as they need… so I consider it a waste of time.

Just feed the fish as you normally do, and avoid overfeeding right before leaving. As I said, any excess food can destroy the quality of the water and reduce their chances of survival.


While fish can survive, on average, between 5 days to 2 weeks without food, it’s best to keep the amount of time they have to go through this to a minimum. After all, it’s survival, not thriving – and not something we want for our pets.

By following my tips, you can ensure your finny friends stay healthy and happy even when you’re not around.

So, plan ahead, prepare your aquarium, and enjoy your trip with peace of mind knowing your underwater companions are well cared for. And even if you are caught unprepared, I have an article sharing what fish eat besides fish food.

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