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How Many Guppies in a 10 Gallon?

How Many Guppies in a 10 Gallon?

Keeping guppies is usually an easy task and not many people, beginners and experts alike, face problems with keeping them. Their general upkeep is easy and feeding them is a breeze.

But there comes a time in every keeper’s life where they stop and wonder, “how many fish can I actually put in there without killing everything inside?”

How many can we keep in a 10-gallon tank? Realistically, a good number to start with a 10-gallon tank assuming water is constantly in a pristine condition should be about 8-10 guppies. While it is possible to keep 15 (or a little more) in a 10 gallon, I personally find it a little too squeezy.

The question is simple and a good one. Overcrowding a tank usually is a spell for disaster yet the amount of fish in a tank should also be at a reasonable number.

Imagine a 10-gallon tank with a single guppy, not only is that sight for sore eyes but its also an incredible waste of space. Similarly, imagine a 10-gallon tank with 50 guppies, it’s only a matter of time before the tank blows up.

How to set up a 10 Gallon Guppy Tank

In today’s article, we cover the specifics on how many fish you should (or can) have in a 10-gallon tank, a complete step by step setup, and the optimum ratios to have!

The Setup

In this section, we take a look at how to put together a nice setup for your guppies. And don’t worry we’ll do it step by step with all the factors you need to consider. For this setup, we’ll be housing 10 guppies.


The 10-gallon tank is a common metric in the fish keeping community. Not only is it easy to find, it usually has many other 3rd party equipment that pairs well with it.

For fish tanks, it is important to note that length is generally better than breadth as you will most probably place your fish tank against a wall so breadth usually not viewed from much or at all.

Material is also important. Most smaller tanks these days are made of plexiglass or acrylic in order to reduce manufacturing and logistical cost (glass is heavier and more difficult to work with).

My recommendation is to go for a glass tank if possible as glass is generally more resistant to scratches. However, both options are good and have their strengths, glass is just a personal preference.

Here are some of the suitable tanks that might interest you:


The heart of your aquarium, the filter brings life to your water. I cannot stress enough how important a good filtration system is for any fish tank.

While some keepers have had success without a filter, most keepers will opt for one simply because it’s so much more efficient in keeping excess nutrients at bay.

A good filtration system should be able to move about 7 to 10 times the volume of water within the tank in an hour.

It also depends on how heavy your bioload (how many fishes) is. That said, there are also quite a few types of aquarium filters available in the market today. But for better understanding, I will briefly go through what the more common ones are that are suitable for your tank.

Sponge filter

Essentially the simplest and cheapest option of filtration. Requires air pump, airline tubing, and the sponge filter.

Pros: Easy to use, reliable and cheap
Cons: Does not move much water, bubbling sound is not for everyone

Internal filter

A convenient choice, usually powerful and can handle higher bioloads as compared to sponge filters due to different media compartments.

Pros: Easy to use, multiple layers of media, high GPH (gallons per hour), quiet
Cons: Slightly more expensive, can get messy during maintenance

Hang on back (HOB) filter

Much like the internal filter, except it is situated outside the tank, hanging on one side of the tank. Also able to handle higher bioloads due to increased volume and separated media compartment, this is also my favorite choice.

Pros: High GPH, separate media compartments, the added volume of water, ease of maintenance due to it being outside the tank
Cons: More expensive, requires a certain water level in the tank if not it will not work properly.

Since we are working with 10 fishes today we’ll probably err on the safe side and choose a filter that is capable of moving 100 gallons (or at least close to) of water an hour.

We will not be recommending sponge filters for this setup due to them having a lower flow rate.

Internal filters (Link to Amazon): 

Hang on back filters (Link to Amazon): 


While some aquariums are set up without any substrate, most hobbyists prefer to include substrate in their aquariums as there are quite a number of benefits.

The substrate provides a more natural-looking habitat and is said to reduce stress in fishes. This also adds to the facade of the aquascape.

Additionally and more importantly, the substrate adds an additional level of filtration. How you may ask? Well, the substrate acts as a medium for beneficial bacteria to colonize and grow, in turn, processing excess nutrients.

What substrate is suitable? Most small rocks, sand, soil, or pebbles will work well with guppies.

Here are some suitable ones to choose from (Link to Amazon):

Generally, a 1-2 inch thick layer of the substrate should suffice and will work wonders in bringing down levels of excess nutrients in the long run. 

Decor and lighting

Both lighting and decor are optional and should only be included if these things are absolutely necessary for you as these are not critical for the guppy’s health. 

Here are some lighting options you can choose from (Link to Amazon) :

How Many Guppies Can You Keep Per Gallon 


The rule of thumb is to have 1 extra gallon of water for every 1 inch of fish, starting from 5 gallons.

As guppies are small fish (growing to a maximum size of 1.5 inches), they do not produce much waste per fish, however, a group will collectively produce more waste than you can imagine.

That said, however, the number of fishes you can keep and should keep is 2 very different questions.

As an experienced keeper, I would tell you that if you can maintain pristine water quality, i.e regular water changes, never overfeeding, regular maintenance, then there shouldn’t be any issue keeping even 20 guppies in a 10-gallon tank.

However, most beginners would probably not be able to do that and keeping 15 guppies in a small 10 gallon is going to be a recipe for disaster.

I would recommend 8-10 guppies as a comfortable number of fish to have in a 10 gallon.

Male to female ratio?

I would recommend no more than 1 male to every 3 females in the tank.

That said, it is important you get the care and husbandry right with all males or all females first before thinking about adding a member of the opposite sex as this can cause quite a few problems. 

Will they breed in the 10-gallon tank?

Absolutely. Without a shred of doubt, they are going to breed. Guppies are extremely prolific and will breed in almost any water condition. However, the better question would be, “should I breed guppies in a 10 gallon?”

Breeding guppies is the easy part, all you need is a male and a female and a bit of time. Within the next month or so you’re probably going to see babies in the tank.

But 10 gallons is almost definitely not enough space if you already have 10 fishes in that tank. However, if you had just a pair and were planning to breed them from the beginning, I’d say you’re doing a great job.

It’s important to note that guppies not only breed quickly, but they also grow quickly too, so be prepared for many generations of guppies if you’re not careful.

Final words

Keeping and raising guppies is not a difficult thing to do since they are hardy fishes and voracious eaters. Although they are prolific, it’s important to note that breeding guppies is a tedious task, and being well prepared for the incoming fries is a must.

Breeding a pair of guppies in a 10 gallon will probably only do you well for the first litter of fries, what about the subsequent litters? Being prepared is key in fish keeping. With proper preparation breeding and raising guppies is a walk in the park.