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How Many Guppies In A 5 Gallon Tank?

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By Lindsey Stanton

guppy fish in aquarium

Guppies are great little fish and they can come in many color variations. They are pretty hardy fish, and keeping them is not too hard. Therefore, they make good fish for beginners like kids or just first-time fish owners in general.

They are resilient, easy to feed, can handle varying water conditions, and they are not too large either. You probably need to know how to house guppies, especially when it comes to keeping them in a tank. Let’s talk about how big guppies grow, how much tank space they need, and how many guppies in a 5-gallon tank are ideal. Keeping more than 3 or 4 guppies is not recommended.

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How Big Do Guppies Grow?

Generally speaking, no guppy is going to grow to be longer than 2 inches in length. As we said, these are relatively small fish, which does bring a certain level of convenience for anyone who owns them. Although female guppies will usually grow to around 2 inches long (this is how long it takes), males tend to be a little shorter and will usually only grow to around 1.5 inches in length. These guys might be small, but their appearance, especially their vastly different colors, has always been a big selling point for the little fish.

different types and colors of guppy rainbow fish
Image Credit: panpilai paipa, Shutterstock

How Much Room Does a Guppy Need?

If you just want to keep a single guppy or just a couple of them, there is a rule that you need to follow. You will need 1 gallon of aquarium space for each inch of fish.

How Many Guppies Per Gallon?

Therefore, a 2-inch guppy will require about 2 gallons of water. If you have two males that are 1.5 inches and 2 females that are 2 inches long, you will need a 7-gallon aquarium, 1 gallon for each inch of fish. Beginners should aim to keep fewer guppies in the same size tank as experts, as having more in one tank starts to make things a little harder. Most aquarists recommend increasing the amount of space according to the number of guppies.

While the rule is that you need 1 gallon for each inch of fish, if you have 20 fish, each 2 inches long (40 inches of fish), you might actually want to keep them in a 50-gallon tank. However, as long as you stick to the minimum spatial requirements, all should be just fine.

lots of guppies swimming
Image Credit: underworld, Shutterstock

How Many Guppies In a 5-Gallon Tank?

So, based on our simple mathematical equation above, it stands to reason that in a 5-gallon tank, you can have 5 inches worth of guppies. So, this means that you could keep two females or three at most if you want to push it. You could keep three males in a 5-gallon tank as well. You could also keep two males and a female, but that is not recommended because they will most likely breed.

The point to remember is 1 inch of fish for each gallon of water. Beginners especially need to stick with this. However, a more experienced fishkeeper could probably house around 4 or 5 guppies in this space, as long as none of them are too large. Never go over 1.5 inches of fish for every gallon of water.

Other Guppy-Keeping Tips

A Suitable Filter

Make sure to have a good filtration unit that engages in all three major types of filtration. All three types, including mechanical, biological, and chemical filtration are important. However, the most important aspect is to have a good biological filtration system. Also, ensure that you have a pretty fine substrate, a few good plants, and a decent lighting system.

red scarlet guppy
Image Credit: Pavaphon Supanantananont, Shutterstock,


Make sure that guppy tank water is always between 74 and 82 degrees Fahrenheit, with the ideal being around 78 degrees. Guppies are tropical fish and they do not do well in cold water (more on tank temperature in this article).


Make sure to feed your guppies good food. High-quality tropical fish flakes should do just fine. You can also supplement some meals with freeze-dried krill, baby mealworms, and insect larvae.

Tank Mates

Guppies are peaceful, which means that you should keep them with other peaceful community fish. They won’t do too well with fish that are much larger, faster, or more aggressive. While these little guys look cool, they won’t be able to stand up to larger and more aggressive fish too well.

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How Many Guppies Should I Get?

Guppies are pretty easy-going fish and if necessary, they can be kept alone. For instance, you might keep one alone if you have a very small tank. Now, while they can be kept alone, it really is not recommended at all.

Guppies are usually seen in groups, and having at least four or five is recommended, as they do like to be around each other. Keep in mind that if you only want two, you should only keep males. Any more than that, and you want to keep guppies at a ratio of two males to one female.

How Many Guppies In a 3-Gallon Tank?

Generally speaking, a single guppy requires 2 gallons of tank space to be happy and healthy. Therefore, in a 3-gallon tank, you should still only keep a single guppy. Sure, you could jam the second one in there, but they really will not be happy at all. They don’t want their space to be cramped. Mathematically speaking, you can keep 0.5 guppies per gallon of water.

How Many Guppies Can You Have In a 10-Gallon Tank?

Alright, so the ideal guppy tank size is 2 gallons per fish, so let’s just divide 10 by 2, which leaves us with a total of 5. You can keep five guppies in a 10-gallon tank and they should be fairly comfortable.

How Many Guppies Per Liter?

So, a gallon of water is 4 liters of water. We have already figured out that each guppy requires 2 gallons of water of tank space to be happy, which means that each guppy requires a full 8 liters of water. Therefore, you cannot keep any guppies in a single liter of water as they require at least 8.

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Final Thoughts

As long as your guppies have enough room and you treat them right, they should live to old age with no problem. Just remember that you should not keep more than 1 inch, or 1.5 inches at most, of fish per gallon of water. Therefore, in a 5-gallon tank, keeping more than three or four guppies is not recommended.

Featured Image Credit: Piqsels

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