How Many Fish Can I Get in a 10-Gallon Tank?

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Starting an aquarium is never easy, which is why many people resort to nano tanks for a safer and easier experience.

After all, it’s easier to set up and manage a 10-gallon tank than a 100-gallon one, right?

That’s correct, but there are some things to consider when setting up your 10-gallon aquarium. The most important of them is the fish that will populate the setup.

So, which fish are fitting for a 10-gallon tank, and how many of them can the system hold?

5 Things to Consider When Selecting Fish for 10-Gallon Tank

As you can see, there’s no clean and easy answer to the problem. Or, should we say, there’s no short answer.

In essence, you have 5 overarching principles to follow when selecting your 10-gallon fish species:

1. Filtration Size

Every aquarium requires optimal filtration to keep the system in good condition. The filter will improve oxygen levels, dilute excess nitrates, clean floating particles, food residues, and dirt, and keep the water clearer.

That being said, the type of filtration to use in your tank depends on your goals, setup, and the tank’s layout. Some filters occupy tank space, while others don’t, as is the case with canister filters.

Fortunately, there are canister filters available for nano tanks, but there are some things to consider before getting one.

The most important one is the output power. You can’t have too much water movement because you have a small system that will feel the effects a lot quicker.

So, you should tweak your filter’s output power according to the system’s needs, making sure that plants, fish, and the overall décor aren’t bothered by the water currents.

2. Live Aquarium Plants

Plants are important, even in nano setups. The challenge is to find plant species that have specifically adapted to nano environments, which can be trickier than you might think.

You have several markers to consider when looking for the perfect nano plants:

  • The maximum size – You obviously don’t want the plants to exceed the tank’s boundaries. So, you should go for small plant species or the dwarf version of larger ones.
  • Low maintenance – You will already be performing more frequent maintenance, which is natural when keeping nano tanks. You don’t need the extra weight of intensive plant maintenance as well. Your goal is to find adaptable and hardy plant species that don’t need a lot of care and maintenance.
  • Compatibility – Some plants don’t mind the smaller space and have adapted to nano setups. These are ideal for your tank, as they can improve water quality and prove beneficial to your fish and shrimp.

Given these factors, some of the best plants to consider for your nano setup include cryptocoryne parva, anubias petite, red tiger lotus, monte carlo, java fern windelov, and many others.

You can research the topic a bit more if you’re looking for as much diversity as possible. However, overall, these should do for the start and as they’re great for pretty much any small aquatic system.

3. Schooling Fish

Many tank fish display schooling behavior, defined by tandem swimming, especially when threatened or stressed.

Schooling fish rely on numbers to keep themselves safe in community setups where they share the same space with other species.

The problem is that these fish need the company of their own for psychological reasons. So, it’s not recommended only to have one fish per tank. This can cause stress, affecting your fish’s temperament and physical prowess.

Stressed fish are timider and more reserved and can experience weaker immune systems, causing them to fall sick more often.

Why am I telling you all this? Because the distinction between schooling and non-schooling fish is important when determining the tank’s size. With only 10 gallons available, you need to choose your fish carefully.

If you’re going for a schooling species, make sure there’s enough room for at least 5-6 specimens. This is the minimum number of fish necessary to form a stable and thriving school.

If the fish are too large, too energetic, or require more swimming space, avoid schooling species altogether.

You’re better off with non-schooling variants that don’t mind the absence of others of the same species.

4. Fish Behavior

You want to stay away from overly aggressive or territorial fish. Especially when it comes to mixing different species that may get into conflicts often. Fish males are generally more abrasive than females, regardless of their species.

This isn’t a problem in a larger setup with plenty of swimming space, plants, rocks, caves, reef structures, and multiple aquatic decorations to serve as hiding areas.

These will defuse much of the aggression by allowing the fish to flee and hide from their aggressors when necessary.

This isn’t much of an option in a 10-gallon setup where the number of hiding areas available will be minimal.

Always prioritize docile and friendly species that don’t mind sharing their space with other creatures.

The ideal fish for your 10-gallon tank shouldn’t mind the tighter space and shouldn’t exhibit too high energy levels.

5. Time for Maintenance

This is often a breaking point for many novice aquarists having a go at nano tanks. The problem with 10-gallon-or-smaller aquariums is the need for more intensive and frequent cleaning, vacuuming, and water changes.

This is to be expected if you think about how the aquatic system works.

In short, your tank inhabitants will produce waste which also comes from a lot of other sources like dead plant matter, food residues, bacterial activity, algae growth, etc.

These residues decay in the water and increase the ammonia and nitrites in the tank. A well-cycled system will transform these chemicals into nitrates which plants use as valuable nutrients.

The good thing is that these take time to accumulate, allowing the filtration system to remove some of them along the way.

You will also perform regular maintenance to reduce the residual matter that could alter the water’s chemistry. But the situation is different in a nano setup.

The waste will accumulate a lot faster because the available environment is so small. As a result, you need to perform more frequent maintenance to prevent chemical imbalances in the water.

As a general rule, the smaller the tank is, the more frequently you need to vacuum the substrate, change the water, and perform other maintenance tasks over time.

You may need to change the water at least 2-3 times per week, depending on the fish species, how many fish and plants you have, and the tank’s layout and design.

So, consider this point carefully before investing in a 10-gallon tank.

What Fish Can Live in a 10-Gallon Tank?

Fortunately, the options are plentiful in this sense. Some of the most popular fish available for nano tanks include golden dwarf barbs, neon tetras, pygmy Corydoras, guppies, bettas, dwarf gourami, etc.

The idea is to look for small fish that don’t need a lot of space, to begin with. Guppies, for instance, grow up to 2.5 inches and only require approximately 2 gallons of water per fish. So, you can have up to 5 of them in your 10-gallon setup.

Other species are even smaller and require even less space. Such is the case with golden barbs, which only grow up to 1.5 inches, allowing you to stock 10 of them in your 10-gallon nano setup.

What is the Biggest Fish for 10-Gallon Tank?

‘Big’ is really just a word in this context because the biggest fish to fit in your 10-gallon setup is still small by any other metric. Bettas or dwarf gouramis may fall into this category.

These grow up to 2.5-3 inches, which is the maximum size recommended for a 10-gallon tank.

Any fish larger than that may not feel comfortable in such a small environment. So, as a general recommendation, make sure that your fish isn’t bigger than 3 inches.

What Other Animals Can Live in 10-Gallon Tank?

If fish-only tanks are not your cup of tea, you can test the waters with different aquatic species along the way.

Fortunately, there are quite a few aquatic animals that feel at home in a 10-gallon system.

These include:

  • African dwarf frog – This tiny amphibian only grows up to 2 inches, making it ideal for our 10-gallon setup. Provide the animal with various logs, caves, and other hiding areas for a safer and more welcoming setting. Floating plants are also a plus since it supports the frogs when they go to the water’s surface to breathe.
  • Dwarf Seahorses – These sound like an exotic option for your nano tank, and that’s because they are. They only grow up to 1.5 inches, are slow movers, and require pristine water conditions to remain healthy. So, only get these ones if you’re ready to perform by-the-book tank maintenance. These creatures can honor you with their presence for up to 2 years when kept in ideal conditions.
  • Hermit crabs – These make for an interesting addition to any aquatic system, thanks to their unique behavior. They will do just fine in a 10-gallon tank, so long as they have a sandy substrate to bury themselves in whenever they need to. Keep at least 2 of them in the same tank because they are social creatures that love to interact with members of the same species.

You can also house various species of snails, since these also don’t require too much room, and some shrimp species, among other animals.

The list is quite expansive in this sense and the challenge isn’t to find the right pets for the job, but to care for them properly.


Nano tanks are more difficult to maintain, but they have an undeniable and unique appeal.

Get yourself a 10-gallon setup, find the ideal tank inhabitants, and follow my recommendations for a problem-free experience and long-term satisfaction.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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