Best Fish for a 10 Gallon Tank or Aquarium

A 10-gallon fish tank gives you a good many options for stocking some beautiful and mesmerizing fish.

However, understanding which species are optimal as a single species fish or those suitable for a community tank can mean the difference between establishing a healthy ecosystem and an aquarium disaster.

The best fish for 10 gallon tanks written beside 2 neon tetras in a planted tankTo save you the hassle of doing a lot of individual research, we’ve put together a list of some of the best fish for a 10 gallon tank or aquarium.

We’ve included some of the most popular species, some that should be kept alone, some that are community fish, and even a snail!

Not All Fish are Suitable for a 10-Gallon Tank

So you’ve been through the arduous task of searching through the best 10 gallon fish tanks, made your choice and are now eyeing up some fish to stock it with.

A 10-gallon tank is considered to be relatively small therefore it’s easy to make mistakes when it comes to stocking your tank. And errors can cause your fish to fail to thrive and may result in premature death.

Not all pet store owners are thoroughly educated in this area, so it’s vital you don’t rely solely on the knowledge of your local aquarium store. By teaching yourself as much as possible about aquarium stocking and fish care, you’re giving yourself every chance of success in developing a great new hobby.


When considering fish for your 10-gallon tank, the first thing to think about is the size and character of your fish.

A small fish may look suitable fundamentally, but their behavior may not. Certain schooling fish, for example, may be too shy if not kept in large numbers – this may result in the fish failing to thrive, being timid and not showing natural behaviors.

Other fish may merely get eaten by a more abundant, more aggressive species. While others still may just plainly be too large for such a small environment.

Taking all the above into consideration, it should be plain to see that choosing the right fish for your size of your aquarium is critical for your success.

Avoid Overcrowding

The number of fish available to stock in your 10-gallon tank should be based on adult-sized fish, as opposed to the size they are when you purchase them.

Obviously, you can upgrade to larger tanks as your fish grow in the future, but if that’s not something you’d consider, being mindful of this fact can save unnecessary frustration.

Also, each species produces different levels of ‘fish load’ – meaning the effect fish have on the aquarium’s ecosystem and water quality.

The balance of the aquarium is determined by the combination of fish waste, the oxygen levels, and the tank’s other contents. The size of the tank will determine how difficult it will be to keep that balance – the smaller the tank, the more careful you need to be, and the less fish you can have.

To work out how many fish to keep in your 10-gallon tank there are two rules you can use as a guide:

One Inch of Fish Per Gallon Rule

This is a commonly-used rule where you calculate one inch of fish per gallon of water. This rule has many flaws and doesn’t allow for the varying shapes of fish, nor the number of accessories, such as filters or decorations.

You need to be mindful of the actual water in the tank once the fixtures are in place and fish are at their adult size. A 10-gallon tank may only hold 9 gallons of water or less, once it is set up. Apply this rule as an estimation.


The Surface Area Rule

Another less-than-perfect rule where this time, the shape of tanks is considered to allow for the varying surface areas of different tanks.

The more surface area a tank has – the more oxygen can be exchanged at the water surface. This has a direct impact on the amount of fish your tank will support, due to the amount of oxygen in the water.

A broad, flat tank may hold the same amount of water as a tall, thin tank. However, their surface areas are very different. The surface area rule tries to cater to this difference.

The flaw here is that it doesn’t allow for the varying shapes of fish. The calculation is 1 inch of fish per 12 inches of surface area (multiply the length and width of your tank together, to get inches of surface area). What you to do is adapt that calculation to allow for the varying body shapes:

  • 1 inch of slim fish per 12-inch surface area
  • 1 inch of ‘full-bodied’ fish per 20-inch surface area
  • ‘Medium-bodied’ fish would fall somewhere in the middle.

Also Consider Compatibility of Fish Species

When considering which fish to stock together, it is essential to research the rules and recommendations surrounding the number of fish suitable for a 10-gallon tank and if you plan to mix species, which can comfortably live with others.

For a full list of compatible fish, please see the following freshwater fish compatibility chart and the marine fish compatibility chart.

A Selection of the Best Fish for 10 Gallon Tanks and Aquariums

Following is a selection of fish species highly suited to the smaller environment of a 10-gallon tank, along with the size they grow to, their water pH requirements and necessary diet.

We’ve done the research so you don’t have to.

Pygmy Corydoras (Corydoras Pygmaeus)

2 pygmy corydoras in a heavily planted tank

  • Origin: South America
  • Maximum size: 1 inch
  • PH of water required: 6.4-7.4
  • Diet: Omnivorous; bloodworms, brine shrimp, mosquito larvae, catfish pellets, flake foods and small amounts of algae.

This tiny little fish is recognizable from other catfish by the stripe running down the length of its body.

One of the few corydoras species able to be stocked in smaller tanks, the pygmy requires a minimum of 10 gallons to live happily in.

The pygmy corydoras need to live in groups of at least eight; otherwise, they become stressed. It is also essential to provide aquarium plants for them to hide in and use sand rather than gravel substrate. Being exposed to gravel for too long will wear their barbels down which will hinder them from being able to search for food or act in a manner natural to the species.

Being tiny and serene, this fish should not share a tank with larger, more hostile fish. They do well in an aquarium with neon tetras and shrimp. They are great little aquarium fish to watch when the right environment has been provided for them – sporadically leaving their school to gulp air at the surface of the water.

Most of their time is spent mid-tank and somewhat shy in nature so bear that in mind when stocking your tank.


Feed them an omnivorous diet of meat and plant life: offering bloodworms, brine shrimp, mosquito larvae, flake foods, catfish pellets and infrequent amounts of algae pellets. Keep the quantities tiny to fit their minuscule mouths.

In a single species tank stock, a minimum of eight, applying the 1 inch of fish per gallon rule as a general guide only. This species is ideally suited to a wide and flat tank.

Neon Tetra (Paracheirodon Innesi)

Close up of 2 neon tetra

  • Origin: South American rainforest
  • Maximum size: 1.2 inches
  • PH of water required: 6-7.5
  • Diet: Omnivorous; flakes, pellets, bloodworms, mosquito larvae and homemade gel fish food.

Neon tetras are extremely popular aquarium fish due to their beautiful (neon-like) colouring, easy-going nature, and low maintenance needs.

Neon tetras will feel comfortable in surroundings similar to their natural environment with relatively low pH levels and soft lighting.

Adding the right amount of driftwood and java fern will adequately give the impression of an Amazon atmosphere.

Be mindful of the fact, these are schooling fish and do need to be kept in groups to thrive – failure to do so will result in your neon tetra becoming stressed.

10 gallons is the minimum to keep at least a group of eight tetras – with larger tanks and groups more optimal. The ideal tankmate for this fish would be other peaceful species such as small schooling fish or corydoras catfish.

As a peaceful fish, the neon tetra is shy and will happily swim actively mid to low levels of the tank.

Neon tetras eat an omnivore diet and are not particularly fussy when it comes to food. They are happy to accept flakes and pellets; however, you should also feed them mosquito larvae, bloodworms, homemade gel fish food, and algae pellets.

Cherry Barb (Puntius Titteya)

Close up of a cherry barb in a planted tank

  • Origin: South-West Sri Lanka
  • Maximum size: 2 inches
  • PH of water required: 6.0-8.0
  • Diet: Omnivorous; high-quality flake, pellets, vegetables, fresh or frozen bloodworms, shrimp brine.

Native to Sri Lanka, Cherry barbs are small, slender-bodied fish. The male cherry barb is a lovely cherry-red color, with the female being a yellow-brownish color with two pink stripes down each side.

As a schooling fish, it ideally needs to be kept in a group of at least five. The cherry barb is best grouped with a two to one female to male ratio, as the male is continuously seeking to breed.

As omnivores, cherry barbs lend towards a more plant-based diet. Feed them premium flake or pellets, with various amounts of vegetables, bloodworms and brine shrimp (frozen or live).

These fish thrive in aquariums that match the natural environment of the cherry barb; with plenty of open space in addition to a heavily planted tank, with numerous options to hide.


Give them a dark substrate, proper filtration and change the water regularly.

You will usually see the cherry barb swimming in the mid to lower levels of your aquarium and is generally peaceful by nature. They tend to make great tankmates with other calm fish and can often be seen chasing each other throughout the aquarium. They very rarely nip other fish although the male cherry barb can become a little aggressive as he reaches adulthood.

Keep them with small, peaceful fish – ideally in a low, wide tank, referring to the ‘one inch of fish per gallon rule’ as a rough guide.

Clown Killifish (Pseudepiplatys Annulatus)

A striped clown killifish isolated on white
© Mirko Rosenau –
  • Origin: West Africa, Guinea, Liberia & Sierra Leone
  • Maximum size: 1 ½ inches
  • PH of water required: 6.0-7.5
  • Diet: Live carnivorous foods; mosquito larvae, fruit flies, shrimp brine, black & white worms.

The clown killifish is an excellent choice for a 10-gallon tank; they are tiny in size and ideally need to be kept with similar-sized fish.

As they are very active jumpers, you need to ensure your aquarium has a hood.

Tanks stocked with driftwood, and a good number of plants allow the clown killifish to feel most in their natural habitat.

In a 10-gallon tank you could keep up to six to eight pairs; however, when referring to your ‘one inch, fish per gallon of water rule,’ remember it is a rough guide, not a definitive one.

Because they prefer to swim in the top six inches of water, the clown killifish requires a long and low tank with a high surface area.

They need a live diet made up black & white worms, fruit flies, shrimp brine and mosquito larvae – most clown killifish will reject frozen varieties.

A substrate is not necessary but if you choose gravel, ensure it’s a type likely to harden the water.

Clown killifish prefer almost no water movement, if you want to keep with other species, consider stocking them with a pair of kuhli loaches.

Kuhli Loach (Pangio Kuhlii)

A kuhli loach resting on the bottom of a gravel lined tank
© Mirko Rosenau –
  • Origin: Indonesia
  • Maximum size: 4 inches
  • PH of water required: 5.5-7.0
  • Diet: Carnivorous; loach pellets & flakes, bloodworms, mosquito larvae, shrimp brine

Due to their easy-to-care-for, peace-loving nature; the kuhli loach is a beautiful choice for both beginners and practiced fish-keepers.

Looking similar to an eel or a snake, they are yellow with dark brown stripes down their body. They use the barbels around their mouths to find food at the bottom of the tank and grow to around four inches as an adult loach.

Both sexes look very similar with the female looking slightly larger when carrying eggs.

Loaches spend most of their time at the bottom of their tank; therefore they require a long, low tank as opposed to a higher one.

Due to their barbels, a sand substrate is ideal for them as gravel hinders their ability to search for food. In addition to the sand substrate, it is a good idea to decorate your aquarium with a hiding place such as a shrimp cave and some dark plant life to create a calming atmosphere for the kuhli loach.


They do not like to be kept on their own, therefore keep them in groups of five or six for optimal care. Don’t stock them with aggressive fish but rather with other peaceful species best suited to broad, low aquariums. Use the surface area rule as a rough guide.

The ideal diet for the kuhli loach is one made up primarily of bloodworms, brine shrimp, and mosquito larvae. Loach pellets and flakes are also a good option. Just be sure that the food will sink to ensure your loach can actually access the feed.

Kuhli loaches are great at interacting with other (peaceful) tankmates. Keeping this species will supply you with endless entertainment.

Fancy Guppy (Poecilia Reticulata)

Close up of a brightly colored fancy guppy

  • Origin: Venezuela & Brazil
  • Maximum size: 2.5 inches
  • PH of water required: 7.5-8.0
  • Diet: Omnivorous; commercial pellets, guppy fish food, mosquito larvae.

Guppies are very popular as far as aquarium fish go: colorful, fascinating to watch and very active. They owe most of their popularity to the way they look, with the male of the species producing a variety of colors and patterns and the females being light brownish with the odd blot of color. They usually display long, flowy tails which are aesthetically beautiful.

A small group of guppies can happily live in a 10-gallon tank, although larger groups in a bigger tank are even better. They are active little swimmers and thrive when they have a lot of space. Guppies generally live in harmony with other peaceful fish such as Corydoras and serene schooling fish.

The guppy has little turned up mouths and will happily accept a variety of food. You can feed them fish food designed for guppies and tropical fish food but ensure you also give them adequate amounts of frozen mosquito larvae.

Guppies love being in groups and remain together while they feed and during times of anxiety. Due to being active swimmers, they are great to watch as they move persistently move around. The male guppy loves to chase the females of the tank and show off by manipulating their bodies into various shapes.

Assassin Snail (Clea Helena)

An assassin snail at the bottom of a tank
By RSX [CC BY-SA 3.0 ], from Wikimedia Commons
  • Origin: Southeast Asia
  • Maximum size: 0.05 inches
  • PH of water required: 7.5-8.0
  • Diet: Carnivorous; live prey, bloodworms, commercial fish food, frozen foods

The assassin snail has an attractive brown and yellow stripped shell which make them a great-looking addition to your aquarium. They don’t usually grow to be more than half an inch in size, and it’s practically impossible to distinguish between the sexes.

Most experts recommend keeping assassin snails in groups of at least four in a minimum of 10-gallons. A sand substrate is ideal for the assassin snail due to the tendency to bury themselves while they wait for their victims. So that their shells don’t lose color, it’s important not to keep the water too soft and keep them in a heated, filtered tank free of harmful pollutants – just as you would with any tropical fish or other invertebrates.

The assassin snail is a hungry little carnivore and will practically eat anything they can, including other snails and the odd dwarf shrimp. Their diet consists of smaller live snails, frozen foods, commercial fish food, and bloodworms. They are an impressive sight to behold as they bury themselves in the sand and wait for their prey to approach for the kill.


Things to be aware of when shopping for assassin snails include ensuring they are active in the tank looking for food sources in the substrate. Check the coloration and condition of their shells as it is a good indication of calcium deficiency. Any signs of their shell not being in peak health should be a warning sign not to purchase.

Introduce this species to your aquarium correctly to avoid placing it under stress, by allowing them to acclimatize to the water conditions.

Keep them in tanks with bigger fish – that doesn’t have a tendency, to eat snails.

Final Thoughts

This list contains some of the best fish for a 10 gallon tank, but it’s only a small taste of the possibilities.

When looking for the perfect fish to stock your small tank with, please do make sure to follow the advice at the top of this article, so you know the fish are suited to such a small environment, and that you will not overstock, or put species together that do not mix.

Thank you for taking the time to visit us today, if you have any questions or feedback, please do leave them in the comment section below.

Happy fish keeping!

B Hamilton

Hey there! I'm Brian, a lifelong enthusiast and fish keeper with a wealth of knowledge and experience on freshwater aquariums, that I love to share on this site. If you have any questions or need any help, please do ask in the comments section below, I'd love to hear from you and will help where I can.

Leave a Comment