How Many Guppies in a 10 Gallon Tank?

Regardless of whether or not you are a newbie to the world of keeping guppies or an experienced fish keeping “old hand” just looking for a little advice, this guide shares with you exactly how many guppies you can safely keep in a 10 gallon tank.

Some experts say that you’re going to want to cap your guppy population at around five when you’re working with a 10 gallon tank. Others, though, say that you can stretch that population out to 10 guppies.

That’s the “sweet spot – between 5 and 10 of these beautiful fish living together in a 10 gallon aquarium.

Let’s dig a little bit deeper into exactly how many guppies you can fit in a 10 gallon tank, how to properly calculate the water needs for your guppies, and so much more.

How Many Guppies in a 10 Gallon Tank?

As highlighted just a moment ago, most professionals in the fish keeping world recommend that you limit your guppy population in 10 gallon tanks to between 5 and 10 fish.

Fewer than five guppies in a 10 gallon tank and you’re really going to start to notice a sort of “empty feeling” throughout your aquarium. More than 10 guppies in the same space, though, will cause a whole host of issues – issues that could devastate your entire guppy population.

Of course, exactly how many guppies you keep in that 10 gallon enclosure really comes down to a handful of things that include:

  • Your aquarium set up
  • The filtration that you have
  • The substrate that you’re working with
  • The plant life inside of your aquarium
  • How frequent you change your water

… And so much more!

We dig into all of that (and then some) below.

group of red and blue guppies swimming in clean water

Calculating Water Needs for Your Guppy Population

One of the most important things you can do when setting up an aquarium (especially when you are working with guppies) is to stick to the “Golden Rule of Water Calculation”.

This Golden Rule basically shakes out to:

  • One inch of fish should have one gallon of water to work with

It’s really important, though, that you properly calculate the water that you are working with and not just go off of the actual tank capacity.

A 10 gallons aquarium, for example, may not actually have a 10 gallon water volume.

Plant life, substrate, filters, heaters, and decorations throughout the aquarium are all going to absorb some of that space. You’re probably (the end of the day) working with seven, eight, or nine gallons of water.

Knowing that adult guppies can get up to about 1.5 inches when they are full grown you’re looking at a maximum guppy population of six or seven (just to be on the safe side).

Calculate your water volume using this Golden Rule before you start to flesh out your guppy population and you’ll be good to go!

What Happens If Too Many Guppies Get Added to a 10 Gallon Tank?

It’s possible to add more fish than six or seven to your 10 gallon tank, but you start to run the risk of overpopulation, feeding issues, fighting issues, and will definitely have to replace your water more frequently than you did with a smaller population.

If you are bent on more guppies and sort of overcrowding your fish tank, you’ll want to be sure that you:

  • Improve your filtration (maybe even invest in an external set up)
  • Upgrade all of your filter media
  • Add a lot more fast-growing live plants to your tank
  • Leverage special (non-gravel) substrate
  • Reduce your overall feeding schedule to once every other day or so
  • And commit to a weekly water change of anywhere between 30% and 50% of your tank water

Those willing to do these things can probably add two or three extra guppies to their 10 gallon tank without any ill effects.

Can You Mix Male and Female Guppies in the Same Tank?

You can certainly mix male and female guppies in the same tank, though you run the risk of them breeding and then having to move the fry out of the tank and into their own enclosure to avoid serious overpopulation issues.

As a general rule of thumb it’s a good idea to try and segregate your male and female guppy populations whenever possible.

If you can’t for one reason or another, though, make sure that you have a plan to deal with the new guppies you’ll inevitably have on your hands before they arrive.

Tank Essentials for Keeping Your Guppies Happy and Healthy

Guppy keepers that want to make sure their fish are happy and healthy are going to want to be sure to leverage the tips and tricks below.

Quality Filtration

High quality filtration is absolutely everything when you are working with a 10 gallon tank, especially if your guppy population is on the higher side of things.

Bigger filters, external filters, and filters running bio media to improve filtration output are going to help you keep those larger populations of guppies healthy.

Good Substrate

The right substrate – a non-gravel substrate – is going to be a little more expensive than gravel, but it’s going to make a world of difference.

Look for a substrate that will do a good job of nature fighting bacteria (helping to break down fish waste before you flush and clean your water). Think about the kinds of plants you’re going to add to this underwater environment and choose a quality substrate that works well with those, too.

It’ll make a world of difference!

Plenty of Underwater Plants

Lots of underwater (and live) plants are going to dramatically improve the quality of water in your fish tank, regardless of whether or not you have a handful of guppies or a “full house”.

Guppy grass, Java ferns, wisteria, Amazon sword, American water weed, and hornworts are just some of the plants that are absolute “must haves” in the guppy enclosure.

These plants help scrub toxins, oxygenate the water, and generally just give your guppies a happier and healthier underwater landscape to live in.

Have Another Tank Size You’re Looking for?

How Many Guppies in a 3-Gallon Tank?

How Many Guppies in a 5-Gallon Tank?

How Many Guppies in a 20-Gallon Tank?

How Many Guppies in a 29-Gallon Tank?