How Many Guppies Can You Keep in a 10-Gallon Tank?

How Many Guppies Can You Keep in a 10-Gallon Tank

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Perhaps you want to start your fishkeeping journey and have decided to start to keep guppies in a 10-gallon tank. That is great! Except, how many guppies can you keep in an aquarium of that size?

First, let us consider why guppies may be the ideal choice for a beginner aquarist. They are small, produce manageable levels of bioload, peaceful, easy to care for, but are colorful and active.

Secondly, why a 10-gallon tank? This is the perfect tank size for new hobbyists because it is large enough for your fish to live happily and healthily, but not too big that it becomes difficult to maintain.

Without further ado, we will reveal how many guppies can ideally live together in a 10-gallon tank.

How Many Guppies to Keep in a 10-Gallon Tank?

As one of the most popular questions asked by amateur fish keepers, this indicates just how many people like to keep guppies when they are starting out.

In general, an adult guppy can reach anywhere from 1.5 to 2 inches in body length. But because they are small and low maintenance does not mean you can simply throw a bunch of them into a tank, feed them pellets every day, and call it a day.

You can use the size to calculate how many guppies are ideal for your tank size. The general rule of thumb in fishkeeping is one gallon of water per inch of fish.

So, 10 divided by 1.5 would be 6.66, or roughly 6 guppies per 10-gallon tank. Note that the number changes depending on the size of your fish.

If this is your first time keeping an aquarium, try to stick to just 5 or 6 guppies. Once you have gotten a hang of it and are more confident, you can start adding more guppies. You should then know how to care for them, including feeding, cleaning the tank, their routine, and breeding.

There are also different types of guppies that grow to various lengths. We recommend referring to a size chart in your local pet store before buying your fish or tank. This can help you figure out how many fish you should get.

Male and Female Guppies

Our general benchmark of 6 adult guppies per tank is suitable for males. If you are keeping females, stick to four of them instead as they are much bigger in size.

It is also important to maintain a ratio of 2:1 or 2 male fishes for every female one. This means around 4 male guppies and 2 female guppies in a ten-gallon tank.

Remember that when you are combining both male and female guppies in a single tank, there is a chance that some of them may breed. We will cover the topic of what you should do in case of breeding later on.

male and female guppies

What Happens When There Are Too Many Guppies?

A common mistake in fishkeeping is overcrowding the tank. It does not matter how large it is, you should not keep too many fish together. It will not end up nicely. In this case, it means you should not place more than 5 to 6 guppies in a 10-gallon aquarium.

The first problem this will cause is an imbalance of water parameters. Your guppies require the right water conditions to thrive. When there are too many of them in a single tank, the ammonia and nitrite content will spike to unhealthy levels and cause sickness (or even death).

More guppies also mean more detritus. The tank will become dirty more easily, thanks to fish excretion, uneaten food, and other organic matters. If you do not clean the tank regularly, it will cause disease among your fish.

There is also the case of personal space. Like any other fish or aquatic creature, guppies need plenty of space to swim around and feel comfortable. If you deprive them of this space, they tend to develop more aggression, which may lead to violence. Yes, this harmless species could end up killing their other tankmates!

Finally, overpopulation in a tank can also cause malnutrition, which is when the fish struggles for enough food, oxygen, and hiding spots. If a guppy does not have sufficient tank volume, it may experience some growth issues.

What to Do After Breeding Guppies

If you are keeping your male and female fishes in the same tank, there is a chance that they will mate and lay eggs to some fry. You have to keep the breeding process in check, or it will get out of control. After all, a guppy can produce up to 120 babies in a single season.

Also, remember to remove the baby fish as they cannot be in the same tank as their adult parents. Never leave them in the same tank as the mature guppies may eat the fry.

Our advice is to give the babies away, sell them, or purchase a new tank where they can grow. One tip to prevent even more baby guppies in the future is to start keeping them in separate aquariums.

A newborn guppy is around 0.25 inches and can fully mature in half a year. They grow around 0.3 inches each month before reaching their full size of two inches.

At the end of the day, your best bet is to start by separating the male and female guppies, even if you plan on breeding them later. Once you are more familiar with how to care for this fish, you can start introducing the different gender to each other.

If you want to keep mating guppies, do not forget to always have a fry tank at hand and keep checking on any pregnant female.

Because each fry is quite tiny, you can keep more than 10 of them in the same tank. However, always keep track of their growth and start moving them to a bigger home once they get bigger.

Tips on Tank Setup

We think most beginners would be happy to start out with a 10-gallon tank and some guppies. They are easy to care for if you have the right setup and don’t overcrowd it.

Tank Requirements for Guppies

In terms of the water parameters and tank requirements, guppies are native to the warm waters in South America. When keeping them at home, try to recreate their natural habitat as best as you can.

They can thrive when the temperature is stable at around 72 to 80 F. And while guppies can tolerate a huge range of water and pH, the ideal one would be 7.0 to 7.2


The filter system in a fish tank is a crucial component. Whether you have a 10-gallon or 30-gallon aquarium, you should be putting the same amount of care, attentiveness, and maintenance.

The best filtration system includes 3 different stages: biological, mechanical, and chemical functions.

This ensures that your filter can remove any organic waste like dead plant matters, fish waste, and excess food, to prevent ammonia buildup. The filter should also be able to remove physical debris and harmful particles from the water to keep it clean.

Finally, it is important to have a chemical function that can filter out any mineral or hard metal from the water source. Especially if you are using tap water for your tank!

Live Plants

Adding live plants can truly brighten up an aquarium and create a more natural home for your guppies. Living plants are not only attractive to see, they can improve water quality and provide hiding spots for guppies.

Some examples you can use in your tank include Guppy grass, Java ferns, Wisteria, and Amazon sword. We also love the texture and visual aesthetics of flowing plants such as Duckweed and Water lettuce.

Furthermore, having plants can minimize algae growth in the rocks, glass, or even substrate. This will in turn help your tank remain clean for longer.

Conclusion: How Many Guppies to Keep in a 10-Gallon Tank?

Overall, you should know that guppies are a truly interesting and captivating species. They are particularly beginner-friendly and will not be too hard to care for. With their bright colors and active behaviors, guppies can be the perfect breed to liven up your home.

If you have bought a 10-gallon tank, the key is to use it for only around five to six guppies. Remember the golden rule: one gallon of water for one inch of fish. Good luck, and happy fishkeeping!

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