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How Long Can Guppies Go Without Food? Diet Explained

How to raise KH in a freshwater aquarium

How Long Can Guppies Go Without Food?

Guppies are some of the most popular freshwater aquarium fish in the fishkeeping hobby, and for a good reason! They are low-maintenance bursts of fun and exciting color in any tank. How long can guppies go without food? Two whole weeks!

Guppy fish are foragers with big appetites, but they can survive without food for surprisingly long periods of time, given the right conditions.

That’s not to say that feeding your guppies just once in a while should become a routine occurrence. This is just another trait that sets guppies apart from most aquarium fish.

Guppy fish are as hardy as they come!

Knowing that your guppies can safely withstand a fasting period offers a bit of peace of mind. All fishkeepers have struggled with making feeding arrangements for fish at least once.

If you’re planning a vacation or have to be away for a short amount of time, a tank of guppies doesn’t require a fish sitter. Let’s see why and how!

Guppy Fish (Poecilia reticulata)

Care levelEasy
TemperamentPeaceful
AppearanceAll colors of the rainbow
LifespanUp to 2 years
Size0.6 to 2.4 inches
DietOmnivorous
FamilyPoeciliidae
Minimum tank capacity5-gallon tank
Tank Set-UpFreshwater | Planted | With substrate
Tank MatesOther peaceful community fish

How Long Can Guppies Go Without Food?Guppy poecilia reticulata

In the wild, freshwater fish are perfectly capable of surviving without a meal for days on end.

The length of time each fish can safely fast depends on its size, age, and hardiness.

Guppies would hardly ever get spoiled with a meal or two per day in their natural habitat. Adult guppy fish have enough fat reserves and body mass to self-sustain when food is scarce.

How long can guppies go without food in an aquarium?

Healthy adult guppies can survive without being fed for up to 2 weeks.

Keep in mind that feeding guppies once every two weeks shouldn’t become a regular thing. But in emergency situations, or if you’re going on vacation, your guppy fish can survive on their own.

Younger guppies, and guppy fry, won’t last as long as adult fish without regular feedings. They simply do not have enough fat stored to power them through a long fasting period.

The larger and more mature a guppy fish is, the longer it can go without food. This general principle stands for guppies in the wild, as well as in captivity.

But because they’re not in the wild and have to self-sustain in a tank, you should take a few fail-safe measures to make sure your guppies will have the best chances of survival while you’re away.

How To Prepare A Guppy Aquarium Before Leaving It For A Few Days

Routine tank maintenance will keep guppies healthy and thriving, but if you’re planning on leaving your guppy fish to fend for themselves for a short amount of time, some extra steps are necessary.

The guppies should be in a cycled tank while you’re away.

A cycled tank with a mature culture of nitrifying bacteria that’s been a home for your guppies for a sufficient amount of time is ideal.

You certainly don’t want to leave guppies behind in a tank that they’ve just been introduced to.

This can cause a potential bacterial imbalance that can wipe out all the fish in a tank quicker than starvation ever could.

An established group of adult guppies will happily cruise a tank they’re familiar with.

Clean the filter/change filter media a few days before leaving.

Every fishkeeper has a loose filter-maintenance schedule they follow, but if you’re planning on being away for more than a week, a quick filter clean-up in your guppy tank is recommended.

Fish waste, dead plant matter, and other debris can clog-up a filter while you’re away if there’s already a significant amount of build-up on it before you leave.

You should try to clean your tank’s filtering system without getting rid of the beneficial bacteria that usually settles on filter media. A quick rinse in a bucket of siphoned old tank water will easily remove the gunk from a sponge filter without losing too much bacteria.

The bacteria will prevent the tank water from turning toxic by converting ammonia and nitrites into non-toxic nitrates.

Do a 50% water change right before leaving.

Speaking of nitrates, a larger than usual water change is highly recommended if your guppies will remain unattended while you’re away.

Routine water changes (30% every two weeks) are meant to help you keep the nitrate concentration in your tank below 10ppm. Nitrates aren’t harmful to fish when kept at a low level.

By doing a 50% water change just before leaving, you give your guppy tank a better chance to stay within normal nitrate concentration levels until you return.

In an established aquarium, nitrifying bacteria will keep your water clean and healthy for fish, so it will be like leaving your tank of guppies on auto-pilot.

If you’re away for two weeks, be sure to do just one of your routine maintenance activities at a time when returning. A “deep-clean” is never recommended in a tank, as it can set-off a dangerous bacterial imbalance.

Install a timer for your tank’s lighting system.

Your guppies will have an easier time living without human intervention if you keep their natural diurnal cycle running even while you’re away.

A good way to make sure that happens is to put a digital timer on your tank lights.

If getting a timer for your tank set-up isn’t feasible, your guppies will be better off with having the lights off for the entire time rather than having them on at all times.

If you do leave the lights off, make sure the guppies at least get some exposure to sunlight, especially if they’re in a planted tank.

You can influence how long guppies can go without food by setting the timer on your lights to create a shorter daylight interval. They will naturally be less active during the night, which means they will have less overall activity, and lower appetites.

To do this, set the timer to keep the lights on for 6-8 hours during day time.

Slightly lower the water temperature in your guppy tank.

Guppies will be less active and preserve more energy if the temperature inside their tank is on the lower end of their optimal temperature range.

Guppy fish should be kept at a temperature between 72-78°F.

Lowering the water temperature is an easy “hack” to use, but it should be done with a good amount of caution. You should only lower it by about two degrees under the temperature that they’re currently accustomed to. And you should do it gradually!

Remove dead plant leaves and/or sick fish.

In an effort to maintain the biological balance inside your guppy tank while you’re away, there are some less pleasant steps you should take.

Take a good look at all the fish and see if any of them show signs of disease, injuries or if any look like they are dying. It’s better to take the plunge and lose a couple of guppies before leaving than to come back to a tank-full of dead guppies.

A dead fish that stays in an unattended tank could cause water toxicity to spike and end up causing ammonia poisoning.

If your guppies are in a planted tank, inspect your live plants as well. Remove dead leaves and plants that look like they are decaying.

Don’t overfeed your guppies before leaving.

You might feel the need to overfeed your guppies just before leaving, but that could end up hurting them a lot more than a longer fasting period could.

Guppy fish can only eat so much at one time, and that leftover food will quickly be broken down into ammonia and nitrites.

Even if you have a fish sitter come by to check on your guppies, you should stress the fact that they shouldn’t overfeed the fish. Otherwise, the water inside their tank will be at risk of becoming toxic.

Should You Use An Automatic Fish Feeder?

Guppy, poecilia reticulata, Male

Some aquarists’ response to the question “How long can guppies go without food?” will be: why don’t you have an automatic fish feeder yet?

Fishkeepers that take a less hands-on approach to their hobby will often rely on automatic feeders to take one item off their checklist, as feedings will get done on a pre-set schedule.

An automatic fish feeder with a feeding station is an awesome tank add-on if leaving your tank unattended for extended periods of time will become a regular thing for you.

The feeder will hold and dispense freeze-dried/dry food, and it can be programmed to feed your guppies once a day or at set intervals. The automatic feeder does this by rotating a divided plate connected to a timer.

If you have guppy fry in the tank you’re going to be away from, an automatic fish feeder isn’t just recommended, it’s necessary. Fry can last without food for significantly shorter periods of time, compared to healthy adult fish. 

If leaving your guppy fish unattended for a week or two isn’t linked to an emergency situation, you should definitely install the automatic feeder a few weeks in advance. This will give you time to see if the guppies are eating all the food portioned out for daily feedings or if you should cut back the portion sizes.

Vacation Feeders | Yay or Nay?

Vacation feeders could be an alternative if you don’t want extra gear, like an automatic feeder, in your guppy tank. They are essentially store-bought slow-release blocks of fish food.

The main drawback of vacation feeders is that some fish will outright ignore them if they don’t like the food. In this case, leaving a slow-release feeding block in an unattended guppy tank can lead to a biological crash.

Uneaten food will continuously break down into more and more ammonia/nitrites, to the point where the water in the tank can become toxic for your guppies.

You could test out a few types of commercial vacation feeders before leaving, and see if you find one that guppies will actually like. They are typically not picky eaters, so you might have some luck if your arrangements allow you to test vacation feeders before going away for a longer period of time.

If you decide to go through with this trial & error process, add one feeding block at a time in your guppy tank. Stop feedings and monitor how the guppies react when fish food gets released.

You might also have to use aquarium test kits to see if the feeding block isn’t increasing your water hardness. The base ingredient in vacation feeders is plaster, which can mess with your water quality.

Most aquarists would rather have their fish fasting for the amount of time they’re away rather than risk the chemical imbalance a vacation feeder can cause.

So, the answer to this “yay or nay” question is purely subjective.

How Long Can Guppy Fry Go Without Food?

GUPPY poecilia reticulata, FEMALE WITH MALE

Guppy fry can survive between 2 to 3 days without food.

There are some circumstances that can allow them to last longer between feedings, but the survival rate of your guppy fry might drop.

Fry that aren’t fed on a regular schedule can develop deformities, get sick, and/or die. They simply do not have the body mass or fat reserves needed to survive without being fed frequently.

You will typically feed guppy fry baby brine shrimp, micro worms, daphnia, vinegar eels, or crushed-up flakes of fish food. But in an established tank, fry can sometimes forage for themselves, and eat algae to survive, which means they could go longer than three days without being fed.

In the wild, and even in a fishkeeper’s outdoor pond, fish fry can grow and mature solely by eating algae and insect larvae.

If you are leaving a tank with guppy fry unattended for longer than three days, you should definitely set up an automatic fish feeder. Even small portions of food given daily can substantially increase the survival rate of most guppy fry.

If the fry share an aquarium with adult guppies, a feeder will deter the adults from eating the fry.

How long guppy fry can go without food also depends on the age/maturity of the fry. Four-month-old guppy juveniles can fast longer than 2-month old fry, which can go without their regular 3/day feedings longer than newborn fry.

What Do Guppies Eat?

Guppy fish eat an omnivorous diet. They’re not picky eaters and will adapt to a varied diet without much fuss. Guppies are also foragers, so they’ll be on a constant search for algae to munch on. 

See here just how much guppy fish love eating algae:

In the wild, a guppy’s diet consists mainly of algae and water insect larvae.

You should feed your guppies a wide variety of food in order to keep them healthy.

Here’s a list of guppy-approved fish food you can leave in an automatic feeder while you’re away:
high-quality flake food for tropical fish;
freeze-dried food;
– brine shrimp;
– bloodworms;
– daphnia.

For routine feedings, you can also feed guppies live food and vegetables like:
– microworms;
– vinegar eels;
– live brine shrimp;
– lettuce;
– peas;
– cucumber.

Under normal circumstances, adult guppy fish should be fed once or twice a day, with portion sizes that they can eat within a minute during each feeding.

Guppy fry will need to be fed in smaller amounts, more frequently (4 to 5 times per day).

Can You Overfeed Guppies?

Do guppies need a filter

Overfeeding guppies is a lot more dangerous than not feeding them for longer periods of time.

This is why most fishkeepers will often prefer to leave fish to fend for themselves for a few days, rather than having an inexperienced fish-sitter overfeed them.

Guppy fish have relatively small stomachs, so overfeeding can quickly cause intestinal blockages, which can be fatal for fish their size.

Guppies should only be fed as much food as they can finish eating in one minute, on a two feedings/day schedule. It’s obvious that they are easy to overfeed, as their ravenous eating habits will make it look like they are constantly starving.

The food that doesn’t get eaten in the first minute of you feeding your guppies will sink to the bottom of the tank and start rotting. So, overfeeding doesn’t mean you’ll have guppies eating “leftovers”, and thus be able to go longer between feedings. 

Overfeeding can only lead to 2 outcomes:
– constipated guppies that become at risk for a number of health issues;
– a decline in water quality due to decomposing leftover food.

Conclusion – How Long Can Guppies Go Without Food?

They can survive for up to 2 weeks if their tank is in a good enough condition at the start of their fasting period. You can safely leave guppies unattended for 10-14 days even without setting up an automatic feeder if you take some precautionary maintenance steps before you go away.

If you’re caring for guppy fry, installing an automatic feeder is highly recommended. Otherwise, they might become quick snacks for adult guppies or end up starving by day 4.

Guppies are among the most resilient freshwater fish, so if you want to go on a short vacation, they’ll do just fine!


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