Why Do Guppy Fish Jump Out of Aquariums?

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Experienced guppy keepers already know this: guppy fish are jumpers. They’re stealthy jumpers and many aquarists report not even noticing it happening.

But is this behavior normal? Why do guppy fish jump out of aquariums? And what can you do about it?

I’ve heard it many times before that the guppies of fellow aquarists have suddenly and mysteriously disappeared from their aquariums, never to be seen again.

Guppies jumping out of the tank, only to be yanked away by a curious pet or dropping to places that aren’t easily accessible in your room are all very likely explanations.

It may baffle you, but guppy fish are pretty good at jumping. They’re able to jump up to eight times their body length.

Some aquarists argue that it’s because water conditions aren’t optimal, others argue that jumping is wired into guppy fish, and it’s really just a survival strategy that may work in the wild, but which fails miserably in home aquaria.

In this article, I discuss the real reasons why guppy fish jump out of their tanks and how you can keep your guppy fish safe.

Keeping Guppies Safe

Before I delve into the possible explanations to why your guppy fish may be inclined to take a “dry dive”, let me first address the issue of safety.

Since it’s an established fact that guppies are jumpers, let’s see what you can do to prevent them from jumping to their death.

The simplest and most straightforward thing to do is to put an aquarium lid on your guppy fish tank and secure it into place, so even when guppies will try to jump, they’ll be unable to pull it off.

It’s even more important to get a lid for your aquarium if you’re not at home during the day and aren’t around to save the guppies that have jumped out.

Likewise, if you have pets that won’t hesitate to eat guppies, they find twitching around on the floor, do make sure you put a lid on your tank.

How High Can Guppies Jump?

Guppies can jump as high as 20-40 cm (8-15 inches) and they even seem to have a technique for it, which was observed by biologist Daphne De Freitas Soares, who has been studying fish behavior.

Soares set up high speed cameras to observe how guppies manage to jump out of their tanks and what she found is that guppies prepare for their jump by swimming backwards in the water (backing up), changing direction and then hurtling themselves into the air.

They’re speedy too — according to Soares, guppies can jump at a speed of four feet per second, hence the need for high speed camera to capture their behavior.

So, if you’re thinking of having guppy fish, do invest in a cover for your aquarium lest you want your fish taking unexpected dives to the floor.

But why do guppies jump out of the tank? What’s behind this behavior? Soares believes it’s an evolutionary response rather than something else.

Why do Guppies Jump?

There are multiple theories why guppies may jump out of their aquarium.

I’ll go over each case, so you’ll know what to check for if your guppies seem a little too eager to get out of their aquariums:

Small Living Space

Jumping out of the aquarium because it’s too small is actually a common reason why many fish will try to escape from an aquarium.

This is actually a reason why any fish may attempt to jump out of the tank. Guppy fish may not grow large, but they do need to be kept with other fish to be comfortable and they do require enough space for swimming.

The smallest tank size recommended for guppies is 10 gallons, but due to their small size, many fish keepers will house them in smaller aquariums, which is not good for them.

A 10-gallon aquarium is a good place to start and depending on its set-up it can hold 5 to 8 guppies.

Some aquarists will overstock their aquariums, once again causing discomfort and bad conditions for guppies, which could also propel them to take a “dry dive”.

An overstocked aquarium is not only uncomfortable because of the lack of enough swimming place, it’s uncomfortable because of the lack of oxygen and abundance of waste products.

Plus, in a small aquarium, water parameters can suddenly and drastically change, making it difficult to restore the balance. A larger aquarium offers more stability in terms of water parameters.

Don’t keep guppy fish in aquariums smaller than 10 gallons and be careful of how you stock the aquarium.

Remember that guppies can also breed out of control and controlling guppy breeding is essential to prevent an overcrowded tank.

There are several ways to control guppy population in the tank such as not mixing the genders or adding other fish into the tank that will feed on fry (e.g. a female betta).


Stress is another big issue that can determine behavioral changes in your fish such as hiding at the bottom of the tank and even jumping out of the aquarium.

Stress can be induced in guppy fish by various things including bad water conditions, an overstocked aquarium, too much traffic around the tank, bad tank mates, pregnancy, etc.

Being constantly stressed can lead to illness, breeding problems, loss of appetite, fading colors, and even death.

Make sure you limit exposure to stress by offering your fish healthy keeping conditions, housing them with compatible tank mates, and avoiding overstocking the aquarium.

Fish have different responses to stress, and many will fall ill if stress factors aren’t eliminated.

Poor Water Conditions

Poor water conditions are a factor that triggers stress in fish and one stress response may explain why some fish — guppies included — will decide to jump out of the aquarium.

This is actually their survival instinct at work, and in every reason, I listed to why guppies will jump out of their tank, their survival instinct is their driving force.

Guppies have well-defined water parameters that they require. For example, the optimal temperature range for guppies is between 72-82 °F (22-28 °C).

Beyond having water within the right parameters for them, they also need stable water parameters, especially when it comes to temperature.

Temperature fluctuations aren’t tolerated well by guppies and they can become stressed and sick if temperatures vary too much.

An aquarium heater will help solve this issue, especially if you live in a climate, where temperatures vary significantly from season to season.

Beyond a heater, guppies require other aquarium equipment to keep the water clean and healthy. These include an aquarium filter, air pump, and live plants.

Water changes are also important, and you should perform water changes every week or every other week — depending on your aquarium stocking level — to keep the water clean.

Want to Explore

What if all the above reasons don’t apply to you? What if your water parameters are great, your guppies aren’t stressed out, and have plenty of room in their aquarium? Why do they still decide it’s time to jump?

As I mentioned at the beginning of this article, this behavior is simply wired into guppies and, indeed, they simply want to explore and diversify their genetic make-up.

Most fish will usually jump for three reasons — either to escape from predators, to catch insects, or to avoid obstacles in their migratory routes.

But none of these are an explanation for the guppy fish’s proclivity to jump. What Soares and her research concluded is that this behavior in guppy fish isn’t influenced by external triggers and it’s something they spontaneously do.

The process of them jumping out looks very deliberate. It starts out with a preparatory phase in which the guppy fish will suddenly stop from swimming, swim backwards, then suddenly change direction and with tail beats and body thrusts they become airborne.

While this strategy may work great in the wild as it can help guppy fish explore waters with a higher abundance of food, move away from heavy predation and avoid in-breeding, the same behavior in captivity has unfortunate consequences.

The only tool to prevent this behavior is to put a weighted-down lid on top of the aquarium, which will keep your guppies safe in their tank.


Even though your guppy fish may seem suicidal to you, as Soares found out, there’s a very good explanation to why these fish have a tendency to spontaneously jump out of the water.

Even though it’s a behavior genetically wired into guppies, it doesn’t mean that you shouldn’t account for all the other possible explanations I listed in this article — stress, small aquarium, poor water conditions — which in many cases will also trigger the same response not only in guppies but other fish too.

Finally, I hope you take the advice of placing a cover on your aquarium to prevent accidental deaths that may occur as a result of your fish jumping out, especially when you’re not around to catch them in action.

Updated: January 13, 2022
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