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How Long Can Betta Fish Go Without Food? Diet, Tank Prep, And More

how many fish in a tank calculator

Planning a vacation and wondering how long can betta fish go without food? You’re already in the “responsible fishkeeper” mindset! Most aquarium fish can survive while fasting for a few days, but some handle it better than others.

Betta fish can go 10 to 14 days without food, but there are a lot of factors that go along with this extended fasting period.

How Long Can Betta Fish Go Without Food? 3 Major Factors

As we’ve just mentioned, betta fish can survive between 10-14 days without food. However, there are some major factors you should consider before leaving your betta fish unattended for such a long period of time.

Leaving your betta fish in a well-established aquarium to which it is already accustomed is important if you want to come back to a minimally-stressed pet fish.

If hiring a fish sitter is out of the question, and you’re going away for more than 3-4 days, there are some critical steps you need to take before leaving.

How long a betta fish can go without food depends on three major factors:

  • Tank size;
  • Filtered vs. Unfiltered Tank;
  • Betta’s general health.

Let’s find out how you can safely prep ahead to keep a betta fish healthy while you’re on vacation!

Betta Fish (Betta splendens)

Care levelEasy
TemperamentAggressive
AppearanceVibrant colorations with long flowing fins
LifespanUp to 3 years
Size2 ½ inches (tail length varies)
DietCarnivorous
FamilyOsphronemidae
Minimum tank capacity3 gallons
Tank Set-UpFreshwater with substrate
Tank MatesSingle male, a sorority of 5 females, or peaceful fish
Alternative nameSiamese fighting fish

Betta fish aren’t generally considered hardy fish, and although they are easy to care for under normal circumstances, they are higher maintenance than most.

They like a relatively narrow water temperature range (75-80°F); they are sometimes picky eaters, and finding them the ideal tank mates can be a challenge.

All things considered, betta fish will efficiently self-sustain for 3-4 days, but there can be some worrisome side effects to being left unattended for 10-14 days.

Here’s a side-by-side view of how a betta fish typically reacts to going 3-4 days without food versus fasting for 10-14 days:

Fasting 3-4 days

Fasting 10-14 days

Hunger Level
  • Normal
  • Might swim-up often to look for food at water surface level
  • Might be settling in starvation mode
  • Uses fat reserves to self-sustain
Stress Level
  • Business as usual
  • Heightened
  • At risk for disease
Water Conditions
  • Normal
  • In major need for a water change
Temperament
  • Peacefully swimming
  • Will flare fins at other tank mates
  • Lethargic and vulnerable
  • Will hide more often
Coloration
  • Bright colors
  • Flowy fins

 

Let’s talk about the three factors that have the most influence on how long you can safely leave a betta fish tank unattended:

Major Factor 1: Tank Size

A smaller aquarium (no smaller than 3 gallons for a betta fish!) will need to be cleaned more often.

So, if you’re leaving a betta into a smaller tank, water conditions might become more harmful to the fish than fasting for an extended period of time.

If your betta fish already lives in a bigger tank or even in a community tank, water conditions will be slower to decline while you’re away.

Major Factor 2: Filtered vs. Unfiltered Tank

Similar to how smaller tanks require more frequent maintenance, so do unfiltered betta tanks.

The unfiltered “fishbowl” trend among betta fishkeepers isn’t typically harmful to pet fish if the bowl has a reasonable size, and bettas have unobstructed access to the water surface for oxygenation.

But, if you’re planning on being away for 10-14 days, the water quality in an unfiltered betta tank is much more likely to drop to dangerous levels than it would in a filtered aquarium.

Major Factor 3: Betta Fish General Health

You have to remember that bettas are individual creatures at the end of the day, and not all betta fish will respond the same even when faced with the same environment.

Their age, metabolism, and general health will come into play, and they will determine how the fish reacts to increased stress levels, being hungry, and having less than ideal water conditions for 10-14 days.

A younger betta fish might handle stress better, but a mature individual might have more fat reserves to tap into when hunger sets in. No two fish will react exactly the same!

Keep in mind that allowing your betta fish to fast for extended periods of time shouldn’t become the norm, neither should it become a routine occurrence. You should only leave your betta fish tank unattended only when absolutely necessary.

How Long Can Betta Fish Fry Go Without Food?

automatic betta fish feeder

Betta babies are relatively high maintenance and can easily die prematurely if their needs aren’t met.

Betta fish fry can go three days without food once they are free-swimming (48 hours after hatching).

They’ll get their nutrients from the egg sack for the first three days of their life, but after that, they’ll need to be fed 3-4 smaller feedings per day.

If you plan on being away from a tank of betta fish fry, an automatic fish feeder might save the day.

You can portion out miniature servings of dried:

  • Daphnia;
  • Brine Shrimp;
  • Fairy Shrimp;
  • MicroWorms;
  • Vinegar Eels.

What Do Betta Fish Eat?

Betta fishbowl

Betta fish are carnivorous. They need to be fed a protein-rich diet.

Fishkeepers typically have a hard time finding store-bought pellet food blends that these picky eaters will actually accept.

As with most aquarium fish, offering a variety of food is the healthiest practice when it comes to feedings. Here’s a list of betta fish approved food:

  • Bloodworms;
  • Brine shrimp;
  • Mosquito larvae;
  • Wingless fruit flies;
  • Mysis Shrimp;
  • Pellets/flakes designed to meet the nutritional needs of betta fish.

Here’s a video to help you decide what is the best food to feed your betta fish:

How To Prepare A Betta Fish Tank Before Leaving It For A Few Days

betta fish not eating

You can influence how long betta fish can go without food by minimizing all the other stress factors that your pet fish might have to deal with while you’re away.

Leaving your pet fish’s aquarium in an ideal condition has more to do with keeping stress levels at a minimum than with influencing your betta’s resilience to fast for more than 3-4 days.

Stress-induced diseases, or just general poor health, can be prevented even if you have to leave your betta tank unattended for 10-14 days.

You’re more likely to come back to a healthy betta fish if you take these seven precautionary steps:

Optimize your betta tank’s conditions

If you’re leaving your betta fish tank unattended because of an emergency, it’s likely you won’t have the time to do much before going away. Vacations are, of course, easier to plan ahead for.

Depending on how much time you have on hand before leaving, you can divide these necessary tank-condition prepping steps into three timelines:

A week before leaving:

  • Check the tank’s filtering system and change/clean clogged-up filtering media.
  • Siphon the gravel to remove leftover food and debris.
  • Check water quality using aquarium test kits (pH level should be between 6.8-7.5).
  • Trim aquatic plants and remove dead plant matter.
  • Check all the gear in your betta tank to ensure they’re working properly (filter, heater, air pump, automatic feeder, light fixtures, etc.).

The day you leave (should also be done in emergency situations):

  • Make sure the water temperature is somewhere between 75-80°F.
  • Perform a larger than usual water change:
    80% for smaller betta tanks (3 gallons) and 50% for larger aquariums (5-10 gallons or more).
    Do a 50% water change even if your betta fish is in a community tank.
  • Do a quick health-check on your betta.
  • Feed your betta fish right before leaving, using the same portion size as you would use during regular feeding.

If going away is a true emergency, and you have absolutely no time to prep ahead, you’ll need to make arrangements for a fish sitter to take over.

Be sure to leave some easy-to-follow guidelines for the fish sitter to follow:

  • Leave a container of tap water to stand for 48-72 hours, and then do a 50% water change;
  • Feed the betta fish this exact portion size of food (having an exact example of how much food to feed your betta will prevent inexperienced fish sitters from overfeeding your fish and causing more harm than good).
  • Leave the lid securely fitted onto the tank (bettas are notorious jumpers!), and don’t fill the aquarium to its maximum capacity (to leave room for your betta to get oxygen at the water’s surface).

Check your betta fish tank’s heater

Betta fish thrive when kept at a tropical water temperature, somewhere in a range between 75-80°F.

That’s the spot where they are at peak health, intense coloration, and engaging in their feisty behavior.

These long-finned splendors can go without the aquarium gear that other pet fish typically rely on:

  • Betta fish can get their entire oxygen supply solely from the water’s surface without an air pump.
  • Bettas can live in unfiltered smaller tanks (with daily water changes to remove ammonia/nitrites).

What your pet betta fish can’t go without is a heater!

Constant water temperature is non-negotiable when it comes to keeping bettas healthy.

Even if you keep the ambient temperature in your house somewhere around 80°F, the water temperature in your aquarium can fluctuate and put unnecessary stress on your betta.

When planning to leave your betta tank unattended for several days in a row:

  • Make sure the heater is working efficiently and is set to keep the water temperature at 75-80°F;
  • Move the tank away from direct sunlight. Smaller tanks, in particular, can easily overheat when left in direct sunlight.
    Sudden temperature changes, and water that’s too hot, can be just as harmful as water that’s too cold.
  • Choose a location for your aquarium that’s draft-free, away from heaters and cooling vents.

Use cooler water temperature to your advantage

If you’re going to be away for 10-14 days, setting the heater in your betta’s tank to keep the water temperature at a lower temperature (73-75°F) will actually work in your favor, extending the number of days that betta fish can go without food.

This water temperature range is still safe for bettas, but it will make them slow down their metabolism.

They will be less active, reducing the number of calories they need to survive and prevent them from burning through their fat reserves.

It’s better for your betta to feel and act a bit more sluggish than usual for ten days than to quickly enter starvation mode after just 3-4 days of fasting.

Put your tank lights on a timer to maintain a diurnal schedule

This precautionary step is meant to keep your betta fish’s stress levels at a minimum since following a diurnal schedule is a great way for fish to self-regulate. 

Not getting any light while you’re away would be just as stressful for bettas as standing in direct sunlight or with the lights constantly on would be.

Hooking your tank lights to a timer, with 8-10 hours of light per day, will help your pet fish carry on, as usual, resting during the night and swimming/exploring during the day.

Leave a securely fitted lid on your betta tank

Betta fish are used to feeding at surface level, and they frequently come up to gulp air using their labyrinth organ.

Because water quality will eventually drop, if you’re away for more than 3-4 days, bettas will come up for oxygen more and even attempt to make a break for it.

Making sure you have a secure lid on your tank is the only way you’ll prevent a betta from jumping out of the tank while it’s unattended.

They’re notorious jumpers as it is, and even though your betta hasn’t managed to make it out of the tank until now, living in suddenly declining water conditions might stress them out to the point where they might just make it.

Better to be safe than sorry!

Make sure your betta can get enough oxygen 

Betta fish are part of the Anabantoidei suborder, which means they are ray-finned freshwater fish that have a defining trait that all fish in this suborder share: a labyrinth organ.

This unique organ allows bettas to supply themselves with oxygen directly from atmospheric air at the water’s surface. That’s how these gorgeous fish manage to survive in hypoxic (with poor oxygenation) habitats in the wild, such as rice paddies, slow streaming water, and large puddles.

This fact considered making sure that your betta fish can oxygenate itself at water surface level is vital.
All you need to do is:

  • make sure that your tank’s lid has unobstructed ventilation areas;
  • don’t fill the tank to maximum capacity.

Do a quick health check-up

Leaving an ill fish unattended for 14 days has nothing to do with how long bettas can go without food.

It simply cannot be done safely, for any amount of time, because you’ll most likely come back to a dead pet fish.

If your betta fish is displaying obvious signs of illness, your only option is to remove it from its community tank (to avoid losing more fish) and transfer it to a larger (5-10 gallon) quarantine tank, following all the steps listed above.

If you’re leaving in an emergency situation, all you can do is hope for the best.

Here’s what you should look for during a health check on a betta fish to see if it can be left unattended:

Healthy Betta

Sick Betta

Actively swimming and exploringAbnormal swimming behaviors
Vibrant colorationDuller coloration
Aggressive | Flaring to show dominanceLethargic | Hiding
No obvious signs of diseaseWhite spots | Bloated
Intact flowing finsClamped or torn-edged fins

Should You Use An Automatic Fish Feeder?

Can betta fish live in a bowl without a filter

Betta fish can sometimes be extremely picky with their food, especially when it comes to pellet food.
They do best on meat-rich diets, but special circumstances might force your pet fish into being less picky. Hunger will often do that to anyone!

Here are a few “ifs” to help you decide whether you should set up an automatic fish feeder for your betta:

  • You’ve had enough time to test out using an automatic fish feeder in your betta tank;
  • Your betta fish actually eats the food dispensed by the feeder for more than ten days in a row;
  • You’ve found the ideal portion sizes to be dispensed to minimize waste and water pollution;
  • It’s a worthwhile purchase (being away for 3-4 days twice a year doesn’t really require setting up a feeder).

Checked all four boxes on this list? Then sure, an automatic fish feeder is a great option to keep your bettas healthy, fed, and stress-free while you’re away.

Conclusion

Going away on vacation, or leaving your betta tank unattended, is wildly different than making pet care arrangements if you were to leave a cat or dog at home.

There are plenty of things that can go wrong when an inexperienced fish sitter has to care for a betta fish. If you do leave someone in charge of keeping your pet fish healthy and fed, make sure to leave detailed instructions.

If a fish sitter isn’t an option, just be sure to follow as many (or all!) of the steps listed above to give your betta the best tank conditions, so it has an easier time adjusting to an extended fasting period.

Fewer stress triggers = better chances of coming back to a healthy (although hungry) betta!


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