How Many Guppies in a 5 Gallon Tank?

Thinking about keeping a 5 gallon aquarium filled with guppies but aren’t sure of where to start?

We can help!

Fish keeping experts say that you want to limit your guppy population to between two and three guppies in a 5 gallon tank. 

Sometimes, though, you can stretch that population by a fish or two – especially if you use the tips and tricks we highlight below.

Let’s jump right in!

How Many Guppies in a 5 Gallon Tank?

A 5 gallon tank might sound like a decent sized aquarium to those that haven’t kept fish before, but it’s really one of the smaller enclosures you’ll find on the market today – and definitely doesn’t have room for a full school of guppies to live and thrive.

Even when we are talking about tiny little guppies!

Guppies, believe it or not, really need a lot more room to roam (so to speak). They don’t enjoy being crowded and their health takes a nosedive when the population starts to get too high in their enclosure.

You might be able to push that to four guppies (maybe five) depending on your tank layout, but beginners are going to want to stick to a pair or triplets for sure.

Guppies in a Tropical Aquarium

Quickly Figure Out How Much Water Each Guppy Needs

Fish keeping experts almost unanimously agree that you want to have a gallon of water volume for every inch of fish you have in the tank.

Any more than that and you end up having a lot of “wasted” water in your aquarium (though your fish probably aren’t going to be all that unhappy with extra space).

Any less than a gallon of water volume for every inch of fish you have in the tank, though, and you start running into some very real problems.

We get deeper into that in just a minute.

Because guppies are going to be anywhere between an inch and 1.5 inches when they are full mature adults they don’t necessarily need a tremendous amount of water. A gallon (and maybe a little more than that) for each of your guppies will generally be enough.

At the same time, you need to remember that your 5 gallon tank doesn’t necessarily mean that there are five full gallons of water to work with.

Water filters, water heaters, plants, substrate, and other aquarium decorations are all going to chew into your water volume. You’re probably going to be working with four or four and a half gallons of water when all is said and done.

This is why we recommend you try and put a hard cap on your guppy population at four, maybe five fish at the maximum.

Avoid Tank Overload – Bad Things Happen with a Fish Population Out of Control

Tank overload (when your fish population goes beyond what your tank can support) can cause a cascade of nightmare situations for your fish to contend with.

Guppies look really small – and they are – but that doesn’t mean that they can be crowded and packed like sardines (pardon the pun).

Too many fish in the same batch of water can cause water chemistry to go haywire, especially when your nitrogen cycles get out of whack.

Bacteria from all that toxic fish waste can plague and disease your fish populations, and you may even have ammonia problems that eliminate the oxygen supply in the water – suffocating your fish without you knowing what’s going on.

Avoid overpopulation as much as possible!

Can Guppies Breed in the Five Gallon Tank? – Should They?

Honestly, it’s a good idea to try and avoid mixing male and female guppies in your 5 gallon tank if that is at all possible.

The last thing you want to worry about is our guppies breeding in this small enclosure, releasing a school of fry that are all going to be competing for resources that get scarcer and scarcer as time goes on.

No, try and keep just male or female guppies in the same enclosure – and do your level best to move any fish fry that are produced in that small enclosure to a bigger one ASAP.

Tips for Keeping Your Guppies Happy and Healthy in a 5 Gallon Tank

Like we mentioned a moment ago, there are a couple of things you can do to sort of bump up your guppy population in a 5 gallon tank – even if you want to stick to just four or five fish at a maximum.

Good Filtration

For starters, you want super high quality filtration to handle all the water in your 5 gallon enclosure.

The overwhelming majority of fish tanks are the size, with internal filters that are halfway decent but really could do with a significant upgrade. External filters may be overkill on a 5 gallon tank, but if you want to guarantee that you are keeping water scrubbed and clean for your fish – especially with overpopulation – it’s not a bad way to go.

Lots of Underwater Plants

Tons of underwater plants (live plants) will make a big difference for keeping your four or five guppies happy and healthy as well.

Guppy grass, watersprite, wisteria, Amazon sword, duckweed, water lettuce, and other plants are game changers for your guppy population.

These plans help oxygenate the water, remove toxins, and provide structure and shelter (not to mention a bit of privacy) for your guppies as well.

Avoid Overfeeding and Overcrowding

With four or five guppies in your 5 gallon enclosure you want to be sure that you sort of scale back feeding schedules to avoid overfeeding – and you are hard limit on 4-5 guppies to avoid overpopulation.

Start feeding your guppies every other day and only add a small pinch at a time. Make sure that each of your guppies gets the fuel they need to stay happy and healthy, though!

Change Water Regularly and Keep Temps Stable

Lastly, you want to be sure that you are staying on top of regular water maintenance schedules and trying to keep your water temperatures as stable as possible.

Changing out between 30% and 50% of your water on a weekly basis will help you avoid toxin buildups and oxygen depletion. It also help you avoid gigantic temperature swings that can do real damage to your guppy population.

Have Another Tank Size You’re Looking for?

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